SWH-I-S Rev K
TM
Installation & Service
Manual
Models: SNR150-100, SNR200-100,
SNA285-125, SNA400-125, AND
SNA500-125
WARNING: If the information in these instructions is not
followed exactly, a fire or explosion may result causing property
damage, personal injury or death.
-- Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance.
-- WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your
building.
• Immediately call your gas supplier from a near by phone.
Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
-- Installation and service must be performed by a qualified
installer, service agency, or the gas supplier.
This manual must only be used by
ƽ WARNING
a qualified heating installer / service
technician. Read all instructions in
this manual before installing. Perform
steps in the order given. Failure to
comply could result in severe personal
injury, death, or substantial property
damage.
Save this manual for future reference.
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Installation & Service Manual
Please read before proceeding
Hazard definitions
The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk levels
or to important information concerning the life of the product.
DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or serious
injury.
ƽ DANGER
WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or serious
injury.
ƽ WARNING
CAUTION indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate
injury.
ƽ CAUTION
CAUTION used without the safety alert symbol indicates a potentially hazardous situation which, if not
avoided, may result in property damage.
CAUTION
NOTICE indicates special instructions on installation, operation, or maintenance that are important but not
related to personal injury or property damage.
NOTICE
If the information in these instructions is
not followed exactly, a fire or explosion
may result causing property damage,
personal injury or death
Installer – Read all instructions, in this
manual before installing. Perform steps in
the order given.
ƽ WARNING
ƽ WARNING
Have this water heater serviced/inspected by a
qualified service technician, at least annually.
-- Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
Failure to comply with the above could result
in severe personal injury, death or substantial
property damage.
-- WHAT TO DO IF YOU SMELL GAS
When calling or writing about the water
heater – Please have the water heater model
and serial number from the water heater
rating plate.
• Do not try to light any appliance.
• Do not touch any electrical switch; do
not use any phone in your building.
• Immediately call your gas supplier
from a near by phone. Follow the
gas supplier’s instructions.
• If you cannot reach your gas supplier,
call the fire department.
-- Installation and service must be
performed by a qualified installer,
service agency, or the gas supplier.
NOTICE
Consider piping and installation when
determining water heater location.
Any claims for damage or shortage in
shipment must be filed immediately against
the transportation company by the consignee.
Factory warranty (shipped with unit) does
not apply to units improperly installed or
improperly operated.
Water heater operation –
• Do not block flow of combustion or ventilation air to
the water heater.
Failure to adhere to the guidelines on this
page can result in severe personal injury,
death, or substantial property damage.
ƽ WARNING
• Should overheating occur or gas supply fail to shut off,
do not turn off or disconnect electrical supply to
circulator. Instead, shut off the gas supply at a location
external to the appliance.
When servicing the water heater –
• To avoid electric shock, disconnect electrical supply
before performing maintenance.
• Do not use this water heater if any part has been under
water. The possible damage to a flooded appliance can
be extensive and present numerous safety hazards. Any
appliance that has been under water must be replaced.
• To avoid severe burns, allow the water heater to cool
before performing maintenance.
3
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Installation & Service Manual
The Shield - How it works...
1. Access cover - front
19. Heat exchanger outlet temperature sensor
Provides access to the gas train and heat exchanger.
This sensor monitors heat exchanger outlet water temperature.
2. Air intake adapter
20. High limit sensor
Allows for the connection of the PVC air intake pipe to the
water heater.
Device that monitors the outlet water temperature. If the
temperature exceeds its setting, it will break the control circuit,
shutting the water heater down.
3. Air pressure switch
The air pressure switch detects blocked inlet conditions.
21. Ignition electrode
Provides direct spark for igniting the burner.
4. Air shroud (500-125 Model Only_Not Shown)
22. Line voltage junction box
The junction box contains the connection points for the line
voltage power.
The air shroud directs air and gas flow into the blower.
5. Blower
The blower pulls in air and gas through the venturi
(item 5). Air and gas mix inside the blower and are pushed into
the burner, where they burn inside the combustion chamber.
23. Low voltage connection board
The connection board is used to connect external low voltage
devices.
6. Burner (not shown)
Made with metal fiber and stainless steel construction, the
burner uses pre-mixed air and gas and provides a 5 to 1 firing
rate.
24. Low voltage wiring connections (knockouts)
Conduit entryway for the low voltage connection board.
25. Power cord
7. Condensate drain connection
Six foot cord allows for quick connection to 120V supply.
Connects the condensate drain line to 1/2" PVC.
26. Pump
8. Electronic Control Module
Circulates water between the tank and the heat exchanger.
The electronic control responds to internal and external signals
and controls the blower, gas valve, and pumps to meet the
demand.
27. Pump relay
Switches power to the pump.
28. Relief valve discharge pipe
9. Electronic display
Protects the heat exchanger from over pressure and
temperature conditions. The relief valve is set at 150 PSI.
The electronic display consists of 7 buttons and a dual line 32-
character liquid crystal display.
29. Stainless steel heat exchanger
10. Flame inspection window
Allows water to flow through specially designed coils for
maximum heat transfer, while providing protection against
flue gas corrosion. The coils are encased in a jacket that
contains the combustion process.
The quartz glass window provides a view of the burner
surface and flame.
11. Flame sensor
Used by the control module to detect the presence of burner
flame.
30. Tank sensor
Used by the control to monitor the temperature of the tank.
12. Flue gas sensor (not shown)
31. Top panel
This sensor monitors the flue gas exit temperature. The control
module will modulate and shut down the water heater if the
flue gas temperature gets too hot. This protects the flue pipe
from overheating.
Removable panel to gain access to the internal components.
32. Vent pipe connection
Allows for the connection of the PVC/CPVC vent pipe system
to the water heater.
13. Gas connection pipe
Threaded pipe connection, either 1/2", 3/4", or 1",
depending on the model. This pipe should be connected
to the incoming gas supply for the purpose of delivering
gas to the water heater.
33. Venturi
The venturi controls air and gas flow into the burner.
34. Water heater drain valve
Location from which the water heater can be drained.
14. Gas shutoff switch (150-100 - - 285-125 Models Only)
An electrical switch designed to cut power from the gas valve to
prevent gas flow to the burner.
35. Water inlet
Copper sweat connection for cold water supply that returns
water from the system to the heat exchanger, either 1-1/2" or 2",
depending on the model.
15. Gas shutoff valve (400-125 -- 500-125 Models Only)
Manual valve used to isolate the gas valve from the gas supply.
36. Water outlet
16. Gas valve
Male NPT water connection that supplies hot water to the
system, either 1-1/2" or 2", depending on the model.
The gas valve senses the negative pressure created by the
blower, allowing gas to flow only if the gas valve is powered and
combustion air is flowing.
37. Over-temp switch (285-125 --500-125 Models Only)
An electrical switch designed to shut down water heater
operation in the event the outer back of the heat exchanger,
directly above the flue connection exceeds 604°F (318°C).
This is a one time switch and could warrant a heat exchanger
replacement. Check the integrity of the rear refractory at the
back of the upper coil if the switch opens.
17. Heat exchanger access cover
Allows access to the combustion side of the heat exchanger
coils.
18. Heat exchanger inlet temperature sensor
This sensor monitors the inlet water temperature to the heat
exchanger.
4
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Installation & Service Manual
The Shield - How it works...
Models SNR150-100 -- SNA285-125
(continued)
31
24
2
25
1
35
32
13
28
9
7
36
34
Front View - Models SNR150-100 -- SNA285-125
Rear View - Models SNR150-100 -- SNA285-125
23
14
13
5
2
2
14
23
22
29
13
18
16
33
5
25
21
10
16
33
29
27
17
9
28
17
11
9
8
3
26
19
20
30
Left Side (inside unit) -- Models SNR150-100 -
SNA285-125
Right Side (inside unit) -- Models SNR150-100 - SNA285-125
5
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Installation & Service Manual
The Shield - How it works...
Model SNA400-125
31
5
15
23
2
8
16
33
13
37
22
17
35
35
29
9
26
32
7
36
30
34
Rear View - Model SNA400-125
Right Side (inside unit) - Model SNA400-125
Model SNA500-125
15
16
5
24
15
25
2
23
8
25
17
29
35
37
32
27
9
3
28
26
7
36
34
Rear View - Model SNA500-125
Right Side (inside unit) - Model SNA500-125
6
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Installation & Service Manual
Ratings
HLW
Model Number
CSA
Water Content
Gallons
Water
Connections
Gas
Connections
Vent/Air Size
Input Modulation Btu/hr
Note: Change “N”
to “L” for L.P. gas
models.
(Note 2)
Min
Max
(Note 1)
3"
SNR150-100
SNR200-100
SNA285-125
SNA400-125
SNA500-125
30,000 - 150,000
92
93
1-1/2"
1-1/2"
2"
1/2"
1/2"
3/4"
1"
40,000 - 199,999
57,000 - 285,000
80,000 - 399,999
100,000 - 500,000
3"
4"
4"
4"
124
125
126
2"
2"
1"
Maximum allowed working pressure is located on the rating plate.
NOTICE
Notes:
1. Shield water heaters require special gas venting. Use
only the vent materials and methods specified in the
Shield Installation and Service Manual.
2. Standard Shield water heaters are equipped to operate
from sea level to 4,500 feet only with no adjustments.
The water heater will de-rate by 4% for each 1,000 feet
above sea level up to 4,500 feet.
3. High altitude Shield water heaters are equipped to
operate from 3,000 to 12,000 feet only with no field
adjustments. The water heater will de-rate by 2% for
each 1,000 feet above 3,000 feet. High altitude models
are manufactured with a different control module
for altitude operation, but the operation given in this
manual remains the same as the standard models. A
high altitude label (as shown in FIG. A) is also affixed
to the unit.
UNIT EQUIPPED FOR
HIGH ALTITUDE
3,000 FT. TO 12,000 FT.
Figure A High Altitude Label Location
7
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Installation & Service Manual
1 Determine water heater location
This appliance requires a special venting
system. The vent connection to the
appliance must be made with the CPVC
pipe section installed in the appliance.
The field provided vent fittings must
be cemented to the CPVC pipe section.
Use only the vent materials, primer and
cement specified in this manual to make
the vent connections. Failure to follow
this warning could result in fire, personal
injury, or death.
Installation must comply with:
ƽ WARNING
•
Local, state, provincial, and national codes, laws,
regulations, and ordinances.
•
•
•
National Fuel Gas Code, ANSI Z223.1 – latest edition.
National Electrical Code.
For Canada only: B149.1 Installation Code, CSA C22.1
Canadian Electrical Code Part 1 and any local codes.
The Shield water heater gas manifold
NOTICE
and controls met safe lighting and other
performance under tests specified in
ANSI Z21.10.3 – latest edition.
Closet and alcove installations
Before locating the water heater, check:
1. Check for nearby connection to:
A closet is any room the water heater is installed in which
is less than 455 cubic feet for SNR150-100 and SNR200-
100 models and 671 cubic feet for the SNA285-125 through
SNA500-125 models.
• Water piping
• Venting connections
• Gas supply piping
An alcove is any room which meets the criteria for a closet
with the exception that it does not have a door.
• Electrical power
2. Locate the appliance so that if water connections should
leak, water damage will not occur. When such locations
cannot be avoided, it is recommended that a suitable
drain pan, adequately drained, be installed under the
appliance. Under no circumstances is the manufacturer
to be held responsible for water damage in connection
with this appliance, or any of its components.
Example: Room dimensions = 6 feet long, 6 feet wide, and
9 foot ceiling = 6 x 6 x 9 = 324 cubic feet. This would be
considered a closet for a Shield Water Heater.
For closet and alcove installations as
ƽ WARNING
shown in FIG.’s 1-1 and 1-2, CPVC or
stainless steel vent material must be used
inside the structure. The ventilating air
openings shown in FIG.’s 1-1 and 1-2 are
required for this arrangement. Failure to
follow this warning could result in fire,
personal injury, or death.
3. Check area around the water heater. Remove any
combustible materials, gasoline and other flammable
liquids.
Failure to keep water heater area clear and
free of combustible materials, gasoline,
ƽ WARNING
and other flammable liquids and vapors
can result in severe personal injury, death,
or substantial property damage.
Provide clearances:
Clearances from combustible materials
1. Hot water pipes—at least 1/4" from combustible
materials.
2. Vent pipe – at least 1" from combustible materials.
3. See FIG.’s 1-1 and 1-2 on page 9 for other clearance
minimums.
4. The Shield water heater must be installed so that gas
control system components are protected from dripping
or spraying water or rain during operation or service.
This appliance is certified as an indoor
ƽ WARNING
Clearances for service access
appliance. Do not install the appliance
1. See FIG.’s 1-1 and 1-2 on page 9 for recommended
service clearances. If you do not provide the minimum
clearances shown, it may not be possible to service the
water heater without removing it from the space.
outdoors or locate where the appliance will
be exposed to freezing temperatures or to
temperatures that exceed 100°F.
Do not install the appliance where the
relative humidity may exceed 93%. Do not
install the appliance where condensation
may form on the inside or outside of the
appliance, or where condensation may fall
onto the appliance.
Failure to install the appliance indoors
could result in severe personal injury,
death, or substantial property damage.
8
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Installation & Service Manual
1 Determine water heater location
(continued)
Figure 1-1 Closet Installation - Minimum Required Clearances
1/4” (6.35 MM)
For closet installations, CPVC,
ƽ WARNING
MINIMUM CLEARANCE
AROUND HOT WATER PIPES
1” (25.4 MM)
polypropylene or stainless steel
vent material MUST BE used in
a closet structure due to elevated
temperatures. Failure to follow
this warning could result in fire,
personal injury, or death.
MINIMUM CLEARANCE
AROUND VENT PIPE
6"
VENTILATING
AIR OPENING
CLOSED DOOR
VENTILATING
AIR OPENING
RECOMMENDED SERVICE
CLEARANCES:
6"
Top
Left/Right Side - 24" (610 mm)
Front - 24" (610 mm)
-
18" (457 mm)
AREA OF EACH OPENING:
1 SQ. INCH PER 1000 BTU PER HOUR INPUT
WITH ALUMINUM OF 100 SQ. INCHES
Figure 1-2 Alcove Installation - Minimum Required Clearances
For alcove installations, CPVC,
ƽ WARNING
polypropylene or stainless steel
vent material MUST BE used
in an alcove structure due to
elevated temperatures. Failure to
follow this warning could result
in fire, personal injury, or death.
1/4” MIINIMUM CLEARANCE
AROUND HOT WATER PIPING
1” MINIMUM CLEARANCE
AROUND VENT PIPE
OPEN
FRONT
RECOMMENDED SERVICE
CLEARANCES:
Top
Left/Right Side - 24" (610 mm)
Front - 24" (610 mm)
-
18" (457 mm)
9
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Installation & Service Manual
1 Determine water heater location
Table 1A Corrosive Contaminants and Sources
Flooring and foundation
Products to avoid:
Flooring
Spray cans containing chloro/fluorocarbons
Permanent wave solutions
The Shield water heater is approved for installation on
combustible flooring, but must never be installed on carpeting.
Do not install the water heater on carpeting
ƽ WARNING
Chlorinated waxes/cleaners
even if foundation is used. Fire can result,
causing severe personal injury, death, or
substantial property damage.
Chlorine-based swimming pool chemicals
Calcium chloride used for thawing
Sodium chloride used for water softening
Refrigerant leaks
When local codes require compliance with NSF 5, the heater
must be sealed to the floor with a food grade silicone to prevent
debris and harborage of vermin under the heater.
If flooding is possible, elevate the water heater sufficiently to
prevent water from reaching the water heater.
Paint or varnish removers
Hydrochloric acid/muriatic acid
Cements and glues
Remove water heater from wood pallet
1. Remove the sides and the top of the crate.
Antistatic fabric softeners used in clothes dryers
2. Remove the blocks on the base of the crate to allow for
easier removal.
Chlorine-type bleaches, detergents, and cleaning solvents
found in household laundry rooms
3. The water heater can then be slid off the base of the crate for
installation.
Adhesives used to fasten building products and other similar
products
Do not drop the water heater or bump the
NOTICE
jacket on the floor or pallet. Damage to the
Areas likely to have contaminants
Dry cleaning/laundry areas and establishments
Swimming pools
water heater can result.
Prevent combustion air contamination
Install air inlet piping for the Shield water heater as described
in this manual. Do not terminate vent/air in locations that can
allow contamination of combustion air. Refer to Table 1A, for
products and areas which may cause contaminated combustion
air.
Metal fabrication plants
Beauty shops
Refrigeration repair shops
Photo processing plants
Ensure that the combustion air will not
ƽ WARNING
contain any of the contaminants in Table 1A.
Contaminated combustion air will damage
the water heater, resulting in possible severe
personal injury, death or substantial property
damage. Do not pipe combustion air near a
swimming pool, for example. Also, avoid
areas subject to exhaust fumes from laundry
facilities. These areas will always contain
contaminants.
Auto body shops
Plastic manufacturing plants
Furniture refinishing areas and establishments
New building construction
Remodeling areas
Garages with workshops
10
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Installation & Service Manual
1 Determine water heater location
(continued)
When removing a water heater from
existing common vent system:
When using an existing vent system to
install a new water heater:
Failure to follow all instructions can result
in flue gas spillage and carbon monoxide
Do not install the Shield water heater
into a common vent with any other
appliance. This will cause flue gas spillage
or appliance malfunction, resulting in
possible severe personal injury, death, or
substantial property damage.
ƽ WARNING
ƽ DANGER
emissions, causing severe personal injury
or death.
Check the following venting components before installing:
• Material - For materials listed for use with this appliance,
see Section 2 - General Venting. For polypropylene or
stainless steel venting, an adapter of the same
manufacturer must be used at the flue collar connection.
Failure to follow all instructions can result
ƽ WARNING
in flue gas spillage and carbon monoxide
emissions, causing severe personal injury
or death.
At the time of removal of an existing water heater, the
following steps shall be followed with each appliance
remaining connected to the common venting system placed
in operation, while the other appliances remaining connected
to the common venting system are not in operation.
• Size - To ensure proper pipe size is in place, see Table 2A.
Check to see that this size is used throughout the vent
system.
• Manufacturer - For a stainless steel or polypropylene
application, you must use only the listed manufacturers
and their type product listed in Tables 2E and 2G for CAT
IV positive pressure venting with flue producing
condensate.
a. Seal any unused openings in the common venting system.
b. Visually inspect the venting system for proper size and
horizontal pitch and determine there is no blockage
or restriction, leakage, corrosion, or other deficiencies,
which could cause an unsafe condition.
• Supports - Non-combustible supports must be in place
allowing a minimum 1/4" rise per foot. The supports
should adequately prevent sagging and vertical slippage,
by distributing the vent system weight. For additional
information, consult the vent manufacturer’s
instructions for installation.
c. Test vent system – Insofar as is practical, close all building
doors and windows and all doors between the space
in which the appliances remaining connected to the
common venting system are located and other spaces of
the building. Turn on clothes dryers and any appliance
not connected to the common venting system. Turn on
any exhaust fans, such as range hoods and bathroom
exhausts, so they will operate at maximum speed. Do not
operate a summer exhaust fan. Close fireplace dampers.
• Terminations - Carefully review Sections 2 through 4 to
ensure requirements for the location of the vent and air
terminations are met and orientation of these fit the
appropriate image from the Sidewall or Vertical
options listed in the General Venting Section. For
stainless steel vent, only use terminations listed in Table
2H for the manufacturer of the installed vent.
d. Place in operation the appliance being inspected. Follow
the lighting instructions. Adjust thermostat so appliance
will operate continuously.
e. Test for spillage at the draft hood relief opening after
5 minutes of main burner operation. Use the flame of a
match or candle, or smoke from a cigarette, cigar, or pipe.
• Seal - With prior requirements met, the system should be
tested to the procedure listed in parts (c) through (f) of
the Removal of an Existing Boiler Section on page 11.
f. After it has been determined that each appliance
remaining connected to the common venting system
properly vents when tested as outlined herein, return
doors, windows, exhaust fans, fireplace dampers, and any
other gas-burning appliance to their previous conditions
of use.
With polypropylene and stainless steel vent, seal and connect
all pipe and components as specified by the vent manufacturer
used; with PVC/CPVC vent, see the Installing Vent or Air
Piping Section on page 20.
If any of these conditions are not met,
ƽ WARNING
the existing system must be updated
g. Any improper operation of the common venting system
should be corrected so the installation conforms with the
National Fuel Gas Code, ANSI Z223.1/NFPA 54 and/or
CAN/CSA B149.1, Natural Gas and Propane Installation
Code. When resizing any portion of the common venting
system, the common venting system should be resized
to approach the minimum size as determined using the
appropriate tables in Part 11 of the National Fuel Gas
Code, ANSI Z223.1/NFPA and/or CAN/CSA B149.1,
Natural Gas and Propane Installation Code.
or replaced for that concern. Failure to
follow all instructions can result in flue gas
spillage and carbon monoxide emissions,
causing severe personal injury or death.
11
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Installation & Service Manual
1 Determine water heater location
Maintain minimum specified clearances for adequate 1. If air is taken directly from outside the building
operation. All installations must allow sufficient space for
servicing the vent connections, water pipe connections, piping
and other auxiliary equipment, as well as the appliance. The
clearance labels on each appliance note the same service and
combustible clearance requirements as shown above.
with no duct, provide two permanent openings to
the equipment room (see FIG. 1-3):
(a) Combustion air opening, with a minimum free area of
one square inch per 4000 Btu/hr input (5.5 cm2 per
KW). This opening must be located within 12" (30 cm)
of the bottom of the enclosure.
Multiple appliances may be installed in a modular water
heater installation. Multiple appliances may be installed
side by side with no clearance between adjacent appliances
because this appliance is approved for zero clearance from
combustible surfaces.
(b) Ventilation air opening, with a minimum free area of
one square inch per 4000 Btu/hr input (5.5 cm2 per
kW). Thisopeningmustbelocatedwithin12"(30cm)of
the top of the enclosure.
Consult the Venting section of this manual for specific
installation instructions for the appropriate type of venting
system that you will be using.
Combustion
and
ventilation
air
requirements for appliances drawing air
from the equipment room
Provisions for combustion and ventilation air must be in
accordance with Air for Combustion and Ventilation, of the
latest edition of the National Fuel Gas Code, ANSI Z223.1, in
Canada, the latest edition of CGA Standard B149 Installation
Code for Gas Burning Appliances and Equipment, or
applicable provisions of the local building codes.
The equipment room MUST be provided with properly sized
openings to assure adequate combustion air and proper
ventilation.
Figure 1-4_Combustion Air Through Ducts
2. If combustion and ventilation air is taken from the
outdoors using
a
duct to deliver the air to the
equipment room, each of the two openings should be
sized based on a minimum free area of one square inch
per 2000 Btu/hr (11 cm2 per kW) of input (see FIG. 1-4).
Figure 1-3_Combustion Air Direct from Outside
12
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Installation & Service Manual
1 Determine water heater location
(continued)
IF NECESSARY FOR
TIGHT CONSTRUCTION
Figure 1-6_Combustion Air from Outside - Single
Opening
Figure 1-5_Combustion Air from Interior Space
3. If air is taken from another interior space, each of the
two openings specified above should have a net free
area of one square inch for each 1000 Btu/hr (22 cm2
per kW) of input, but not less than 100 square inches
(645 cm2) (see FIG. 1-5).
4. If a single combustion air opening is provided to bring
combustion air in directly from the outdoors, the opening
must be sized based on a minimum free area of one square
inch per 3000 Btu/hr (7 cm2 per kW). This opening must
be located within 12" (30 cm) of the top of the enclosure
(see FIG. 1-6).
TABLE - 1B
MINIMUM RECOMMENDED COMBUSTION
AIR SUPPLY TO EQUIPMENT ROOM
FIG. 1-4
FIG. 1-3
*Outside Air from
2 Openings Directly from
Outdoors
FIG. 1-5
FIG. 1-6
*Outside Air from
2 Ducts Delivered from
Outdoors
**Inside Air from
2 Ducts Delivered from Interior
Space
Model
Number
*Outside Air from
1 Opening Directly
from Outdoors, in2
Top
Bottom
Top
Bottom
Opening, in2
75
Top
Opening, in2
150
Bottom
Opening, in2
150
Opening, in2 Opening, in2 Opening, in2
38
38
75
(484 cm2)
100
50
SNR150-100
SNR200-100
SNA285-125
SNA400-125
(246 cm2)
50
(246 cm2)
50
(484 cm2)
100
(968 cm2)
200
(968 cm2)
200
(323 cm2)
67
(323 cm2)
72
(323 cm2)
72
(646 cm2)
143
(646 cm2)
143
(1,291 cm2)
285
(1,291 cm2)
285
(433 cm2)
95
(465 cm2)
100
(465 cm2)
100
(923 cm2)
200
(923 cm2)
200
(1,839 cm2)
400
(1,839 cm2)
400
(613 cm2)
134
(646 cm2)
(646 cm2)
(1,291 cm2)
(1,291 cm2)
(2,581 cm2)
(2,581 cm2)
(865 cm2)
125
(807 cm2)
125
(807 cm2)
250
(1,613 cm2)
250
(1,613 cm2)
500
(3,226 cm2)
500
(3,226 cm2)
167
(1,078 cm2)
SNA500-125
*Outside air openings shall directly communicate with the outdoors. When combustion air is drawn from the outside through a
duct, the net free area of each of the two openings must have twice (2 times) the free area required for Outside Air/2 Openings.
The above requirements are for the water heater only; additional gas fired appliances in the equipment room will require an
increase in the net free area to supply adequate combustion air for all appliances.
**Combined interior space must be 50 cubic feet per 1,000 Btu/hr input. Buildings MUST NOT be of *“Tight Construction”.
For buildings of *“Tight Construction”, provide air openings into the building from outside.
*No combustion air openings are needed when the water heater is installed in a space with a volume NO LESS than 50 cubic feet
per 1,000 Btu/hr of all installed gas fired appliances. Buildings MUST NOT be of *“Tight Construction”.
*“Tight Construction” is defined as a building with less than 0.40 ACH (air changes per hour).
13
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Installation & Service Manual
1 Determine water heater location
The combustion air supply must be completely free of any
flammable vapors that may ignite or chemical fumes which
may be corrosive to the appliance. Common corrosive chemical
fumes which must be avoided are fluorocarbons and other
halogenated compounds, most commonly present as refrigerants
or solvents, such as Freon, trichlorethylene, perchlorethylene,
chlorine, etc. These chemicals, when burned, form acids which
quickly attack the stainless steel heat exchanger, headers, flue
collectors, and the vent system.
Combustion air requirements are based on the latest edition
of the National Fuel Gas Code, ANSI Z223.1; in Canada refer
to the latest edition of CGA Standard CAN B149.1. Check all
local code requirements for combustion air.
All dimensions based on net free area in square inches. Metal
louvers or screens reduce the free area of a combustion air
opening a minimum of approximately 25%. Check with
louver manufacturers for exact net free area of louvers.
Where two openings are provided, one must be within 12"
(30cm) of the ceiling and one must be within 12" (30cm) of
the floor of the equipment room. Each opening must have
net free area as specified in the chart above (Table 1B). Single
openings shall commence within 12" (30cm) of the ceiling.
The result is improper combustion and a non-warrantable,
premature appliance failure.
EXHAUST FANS: Any fan or equipment which exhausts air
from the equipment room may deplete the combustion air
supply and/or cause a downdraft in the venting system. Spillage
of flue products from the venting system into an occupied
living space can cause a very hazardous condition that must be
immediately corrected. If a fan is used to supply combustion
air to the equipment room, the installer must make sure that it
does not cause drafts which could lead to nuisance operational
problems with the appliance.
Under no circumstances should the
ƽ CAUTION
equipment room ever be under negative
pressure. Particular care should be taken
where exhaust fans, attic fans, clothes
dryers, compressors, air handling units,
etc., may take away air from the unit.
14
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Installation & Service Manual
2 General venting
Direct venting options - Sidewall Vent
Figure 2-2 PVC/CPVC Concentric Sidewall Termination
- See page 27 for more details
Figure 2-1 Two-Pipe Sidewall Termination - See page
23 for more details
Direct venting options - Vertical Vent
Figure 2-3 Two-Pipe Vertical Termination Figure 2-4 PVC/CPVC Concentric
Figure 2-5 Vertical Vent,
Sidewall Air - See page 19 for
more details
- See page 30 for more details
Vertical Termination - See page 32
for more details
15
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Installation & Service Manual
2 General venting
Install vent and combustion air piping
The Shield water heater must be vented and
supplied with combustion and ventilation
air as described in this section. Ensure the
vent and air piping and the combustion
air supply comply with these instructions
regarding vent system, air system, and
combustion air quality. See also Section 1
of this manual.
The Shield water heater vent and air piping can be installed
through the roof or through a sidewall. Follow the procedures
in this manual for the method chosen. Refer to the information
in this manual to determine acceptable vent and air piping
length.
ƽ DANGER
You may use any of the vent/air piping methods covered in this
manual. Do not attempt to install the Shield water heater using
any other means.
Inspect finished vent and air piping
thoroughly to ensure all are airtight and
comply with the instructions provided and
with all requirements of applicable codes.
Failure to provide a properly installed vent
and air system will cause severe personal
injury or death.
You must also install air piping from outside to the water
heater air intake adapter unless following the Optional Room
Air instructions on page 19 of this manual. The resultant
installation is direct vent (sealed combustion).
Air intake/vent connections
1. Combustion Air Intake Connector (FIG. 2-6) - Used to
provide combustion air directly to the unit from outdoors. A
fitting is provided on the unit for final connection.
Combustion air piping must be supported per guidelines
listed in the National Mechanical Code, Section 305, Table
305.4 or as local codes dictate.
This appliance requires a special venting
system. Use only approved stainless steel,
PVC, CPVC or polypropylene pipe and
fittings listed in Tables 2D, 2E, and 2G for
vent pipe, and fittings. Failure to comply
could result in severe personal injury,
death, or substantial property damage.
ƽ WARNING
2. Vent Connector (FIG.'s 2-7 thru 2-9) - Used to provide a
passageway for conveying combustion gases to the
outside. A transition fitting is provided on the unit for
final connection. Vent piping must be supported per the
National Building Code, Section 305, Table 305.4 or as
local codes dictate.
DO NOT mix components from different
systems. The vent system could fail,
causing leakage of flue products into the
living space. Mixing of venting materials
will void the warranty and certification of
the appliance.
ƽ WARNING
Figure 2-6 Near Water Heater Air Piping
Installation must comply with local
requirements and with the National
Fuel Gas Code, ANSI Z223.1 for U.S.
installations or CSA B149.1 for Canadian
installations.
NOTICE
AIR
For closet and alcove installations, CPVC,
polypropylene or stainless steel material
MUST BE used in a closet/alcove structure.
Failure to follow this warning could result
in fire, personal injury, or death.
ƽ WARNING
Improper installation of venting systems
may result in injury or death.
ƽ CAUTION
Follow the instructions in Section 1, page
11 of this manual when removing a water
heater from an existing vent system.
NOTICE
Do not connect any other appliance to
the vent pipe or multiple water heaters to
a common vent pipe. Failure to comply
could result in severe personal injury,
death, or substantial property damage.
ƽ WARNING
16
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Installation & Service Manual
2 General venting
(continued)
Requirements for installation in
Canada
Minimum
/
Maximum
allowable
combustion air and vent piping lengths
are as follows:
1. Installations must be made with a vent pipe system
certified to ULC-S636.
Combustion Air = 12 equivalent feet minimum / 100
equivalent feet maximum
2. The first three (3) feet of plastic vent pipe from the
appliance flue outlet must be readily accessible for visual
inspection.
Vent = 12 equivalent feet minimum / 100 equivalent feet
maximum
3. The components of the certified vent system must not be
interchanged with other vent systems or unlisted
pipe/fittings. For concentric vent installations, the inner
vent tube must be replaced with field supplied certifiedvent
material to comply with this requirement.
When determining equivalent combustion air and vent
length, add 5 feet for each 90° elbow and 3 feet for each 45°
elbow.
EXAMPLE: 20 feet of PVC pipe + (4) 90° elbows + (2) 45°
elbows + (1) concentric vent kit (CVK3003) = 49 equivalent
feet of piping.
4. The 3" Concentric Vent Kit available from Lochinvar (see
Section 3 – Sidewall Termination – Optional Concentric
Vent) and the 3" Concentric Vent Kit available from IPEX
are both approved for use on the Shield water heater. Both
kits are listed to the ULC-S636 standard for use in Canada.
The appliance output rating will reduce
NOTICE
by up to 1.5% for each 25 feet of vent
length.
Sizing
Table 2B Concentric Vent Kit Equivalent Vent Lengths
The Shield water heater uses model specific combustion air
intake and vent piping sizes as detailed in Table 2A below.
Kit
Equivalent
Model
Number Vent Length
SNR150-100 -- SNR200-100 CVK3003
Table 2A Air Intake/Vent Piping Sizes
3 feet
3 feet
5 feet
30 feet
SNA285-125
SNA400-125
SNA500-125
CVK3007
CVK3007
CVK3007
Model
SNR150-100 -- SNR200-100
Air Intake
3 inches
Vent
3 inches
4 inches
SNA285-125 -- SNA500-125
4 inches
Increasing or decreasing combustion air
or vent piping sizes is not authorized.
NOTICE
17
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Installation & Service Manual
2 General venting
Materials
Air inlet pipe materials:
The PVC, CPVC, or ABS air inlet pipe should be cleaned and
sealed with the pipe manufacturer’s recommended solvents
and standard commercial pipe cement for the material used.
The PVC, CPVC, ABS, Dryer Vent or Flex Duct air inlet pipe
should use a silicone sealant to ensure a proper seal at the
appliance connection and the air inlet cap connection. Dryer
vent or flex duct should use a screw type clamp to seal the vent
to the appliance air inlet and the air inlet cap. Proper sealing
of the air inlet pipe ensures that combustion air will be free of
contaminants and supplied in proper volume.
The air inlet pipe(s) must be sealed. Choose acceptable
combustion air inlet pipe materials from the following list:
PVC, CPVC, Polypropylene or ABS
Dryer Vent or Sealed Flexible Duct (not recommended
for rooftop air inlet)
Galvanized steel vent pipe with joints and seams sealed as
specified in this section.
Type “B” double-wall vent with joints and seams sealed as
specified in this section.
AL29-4C, stainless steel material to be sealed to
specification of its manufacturer.
Follow the polypropylene manufacturer’s instructions when
using polypropylene material as an inlet pipe.
*Plastic pipe may require an adapter (not provided) to
transition between the air inlet connection on the appliance
and the plastic air inlet pipe.
When a sidewall or vertical rooftop combustion air supply
system is disconnected for any reason, the air inlet pipe must
be resealed to ensure that combustion air will be free of
contaminants and supplied in proper volume.
Using air intake materials other than
those specified can result in personal
injury, death or property damage.
ƽ WARNING
Failure to properly seal all joints and seams
ƽ DANGER
as required in the air inlet piping may
result in flue gas recirculation, spillage
of flue products and carbon monoxide
emissions causing severe personal injury
or death.
The use of double-wall vent or insulated
NOTICE
material for the combustion air inlet pipe is
recommended in cold climates to prevent
the condensation of airborne moisture in
the incoming combustion air.
Sealing of Type “B” double-wall vent material or galvanized
vent pipe material used for air inlet piping on a sidewall or
vertical rooftop Combustion Air Supply System:
a. Seal all joints and seams of the air inlet pipe using either
Aluminum Foil Duct Tape meeting UL Standard 723 or
181A-P or a high quality UL Listed silicone sealant such as
those manufactured by Dow Corning or General Electric.
b. Do not install seams of vent pipe on the bottom of
horizontal runs.
c. Secure all joints with a minimum of three (3) sheet metal
screws or pop rivets. Apply Aluminum Foil Duct Tape or
silicone sealant to all screws or rivets installed in the vent
pipe.
d. Ensure that the air inlet pipes are properly supported.
18
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Installation & Service Manual
2 General venting
(continued)
Air contamination
Optional room air
Pool and laundry products and common household and hobby
products often contain fluorine or chlorine compounds. When
these chemicals pass through the water heater, they can form
strong acids. The acid can eat through the water heater wall,
causing serious damage and presenting a possible threat of flue
gas spillage or water heater water leakage into the building.
Optional room air is intended for
commercial applications. Combustion
air piping to the outside is recommended
for residential applications.
NOTICE
Commercial applications utilizing the Shield water heater
may be installed with a single pipe carrying the flue products
to the outside while using combustion air from the equipment Please read the information given in Table 1A, page 10, listing
room. In order to use the room air venting option the contaminants and areas likely to contain them. If contaminating
following conditions and considerations must be followed.
chemicals will be present near the location of the water heater
combustion air inlet, have your installer pipe the water heater
combustion air and vent to another location, per this manual.
•
The unit MUST be installed with the appropriate
room air provisions.
•
The equipment room MUST be provided with
properly sized openings to assure adequate
combustion air. Please refer to instructions provided
with the room air kit.
If the water heater combustion air inlet is
ƽ WARNING
located in a laundry room or pool facility,
for example, these areas will always contain
hazardous contaminants.
•
•
There will be a noticeable increase in the noise level
during normal operation from the inlet air opening.
Using the room air configuration makes the unit
vulnerable to combustion air contamination from
within the building. Please review Section 1,
Prevent Combustion Air Contamination, to ensure
proper installation.
Vent system and terminations must comply with the
standard venting instructions set forth in this
manual.
To prevent the potential of severe personal
ƽ WARNING
injury or death, check for areas and products
listed in Table 1A, page 10 before installing
the water heater or air inlet piping.
If contaminants are found, you MUST:
• Remove contaminants permanently.
—OR—
•
• Relocate air inlet and vent terminations
to other areas.
When utilizing the single pipe method,
ƽ WARNING
provisions for combustion and ventilation
air must be in accordance with Air for
Combustion and Ventilation, of the latest
edition of the National Fuel Gas Code,
ANSI Z223.1, in Canada, the latest edition
of CGA Standard B149 Installation
Code for Gas Burning Appliances and
Equipment, or applicable provisions of
the local building codes.
19
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Installation & Service Manual
2 General venting
1. Work from the water heater to vent or air termination.
Do not exceed the lengths given in this manual for the
air or vent piping.
PVC/CPVC
This product has been approved for use with the PVC/CPVC
vent materials listed in Table 3D.
2. Cut pipe to the required lengths and deburr the inside
and outside of the pipe ends.
Installing vent and air piping
3. Chamfer outside of each pipe end to ensure even
cement distribution when joining.
The vent connection to the appliance must
ƽ WARNING
be made with the starter CPVC pipe section
provided with the appliance if PVC/CPVC
vent is to be used. The field provided
vent fittings must be cemented to the
CPVC pipe section using an “All Purpose
Cement” suitable for PVC and CPVC pipe.
Use only the vent materials, primer, and
cement specified in Table 3D to make
the vent connections. Failure to follow
this warning could result in fire, personal
injury, or death.
4. Clean all pipe ends and fittings using a clean dry rag.
(Moisturewillretardcuringanddirtorgreasewillprevent
adhesion.)
5. Dry fit vent or air piping to ensure proper fit up before
assembling any joint. The pipe should go a third to
two-thirds into the fitting to ensure proper sealing after
cement is applied.
6. Priming and Cementing:
a. Handle fittings and pipes carefully to prevent
contamination of surfaces.
Use only cleaners, primers, and solvents
NOTICE
b. Apply a liberal even coat of primer to the fitting
socket and to the pipe end to approximately 1/2"
beyond the socket depth.
that are approved for the materials which
are joined together.
All PVC vent pipes must be glued, properly
NOTICE
c. Apply a second primer coat to the fitting socket.
supported, and the exhaust must be pitched
a minimum of a 1/4 inch per foot back to
the water heater (to allow drainage of
condensate).
d. While primer is still wet, apply an even coat of
approved cement to the pipe equal to the depth of
the fitting socket along with an even coat of
approved cement to the fitting socket.
Insulation should not be used on PVC
ƽ WARNING
or CPVC venting materials. The use of
e. Apply a second coat of cement to the pipe.
insulation will cause increased vent wall
temperatures, which could result in vent
pipe failure.
f. While the cement is still wet, insert the pipe into
the fitting, if possible twist the pipe a 1/4 turn as
you insert it. NOTE: If voids are present,
sufficient cement was not applied and joint could
be defective.
Table 2D PVC/CPVC Vent Pipe, and Fittings
Approved PVC/CPVC Vent Pipe and Fittings
g. Wipeexcesscementfromthejointremovingringor
beads as it will needlessly soften the pipe.
Item
Material
PVC Schedule 40, 80 ANSI/ASTM D1785
PVC - DWV ANSI/ASTM D2665
CPVC Schedule 40, 80 ANSI/ASTM F441
Standard
Figure 2-7 Near Water Heater PVC/CPVC Venting
Vent pipe
PVC Schedule 40
ANSI/ASTM D2466
ANSI/ASTM D2467
ANSI/ASTM F439
ANSI/ASTM D2564
ANSI/ASTM F493
VENT
Vent fittings PVC Schedule 80
CPVC Schedule 80
Pipe Cement / PVC
Primer
CPVC
NOTICE: DO NOT USE CELLULAR (FOAM) CORE PIPE
4" CPVC PIPE INSTALLED IN THE
WATER HEATER MUST BE USED
FOR VENT CONNECTION
NOTE: In Canada, CPVC and PVC vent pipe, fittings and cement/
primer must be ULC-S636 certified.
NOTE: CPVC VENT PIPE AND VENT FITTINGS MUST BE USED
IN CLOSET AND ALCOVE INSTALLATIONS.
20
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Installation & Service Manual
2 General venting
(continued)
Polypropylene
Use only the adapters and vent system listed
in Tables 2E and 2F. DO NOT mix vent
systems of different types or manufacturers.
Failure to comply could result in severe
personal injury, death, or substantial
property damage.
ƽ WARNING
This product has been approved for use with polypropylene
vent with the manufacturers listed in Table 2E.
All terminations must comply with listed options in this manual
and be a single-wall vent offering.
For use of flex pipe, it is recommended to have the vent material
in 32°F or higher ambient space before bending at installation.
No bends should be made to greater than 45° and ONLY
installed in vertical or near vertical installations.
Installations must comply with applicable
national, state, and local codes. For
Canadian installation, polypropylene vent
must be listed as a ULC-S636 approved
system.
NOTICE
NOTICE
For support and special connections required, see the
manufacturer's instructions. All vent is to conform to standard
diameter and equivalent length requirements established.
Installation of a polypropylene vent system
should adhere to the vent manufacturer’s
installation instructions supplied with the
vent system.
Table 2E Polypropylene Vent Pipe and Fittings
Approved Polypropylene Vent Manufacturers
Make
Model
Centrotherm Eco Systems
InnoFlue SW/Flex
Duravent (M & G Group)
PolyPro Single-Wall / PolyPro Flex
The installer must use a specific vent
NOTICE
starter adapter at the flue collar
connection. The adapter is supplied by
the vent manufacturer to adapt to its vent
system. See Table 2F for approved vent
adapters. Discard CPVC starter piece.
Figure 2-8 Near Water Heater Polypropylene Venting
All vent connections MUST be secured by
the vent manufacturer's joint connector
(FIG. 2-8).
NOTICE
POLYPROPYLENE
ADAPTER
Insulation should not be used on
polypropylene venting materials. The use
of insulation will cause increased vent wall
temperatures, which could result in vent
pipe failure.
ƽ WARNING
IMG00156
JOINT CONNECTOR REQUIRED AT ALL
COMPONENT CONNECTIONS OF VENT SYSTEM
Table 2F Approved PolypropyleneTerminations
Duravent Polypro
Centrotherm InnoFlue SW
Model
Polypropylene
Adapter
Joint
Connector
Sidewall Retaining
Bracket*
Polypropylene
Joint
Connector
Sidewall Adapter*
Sidewall Kit*
Adapter
3PPS-AD
4PPS-AD
SNR150 - SNR200 ISAAL0303
SNA285 - SNA500 ISAAL0404
IANS03
IANS04
IATP0303
IATP0404
ISTAGL0303
ISTAGL0404
3PPS-LB
4PPS-LB
3PPS-HLK
4PPS-HLK
* These parts are only needed if the sidewall termination assembly is used (see FIG. 3-4B on page 25).
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21
TM
Installation & Service Manual
2 General venting
Installation of a stainless steel vent system
should adhere to the stainless steel vent
manufacturer’s installation instructions
supplied with the vent system.
Stainless steel vent
NOTICE
This product has been approved for use with stainless steel
using the manufacturers listed in Table 2G.
Use only the materials, vent systems, and
ƽ WARNING
Figure 2-9 Near Water Heater Stainless Steel Venting
terminations listed in Tables 2G and 2H.
DO NOT mix vent systems of different
types or manufacturers. Failure to comply
could result in severe personal injury,
death, or substantial property damage.
VENT
The installer must use a specific vent starter
NOTICE
adapter at the flue collar connection,
supplied by the vent manufacturer to
adapt to its vent system. See Table 2H for
approved vent adapters. Discard CPVC
starter piece.
3" S.S. ADAPTER
Installations must comply with applicable
NOTICE
national, state, and local codes. Stainless
steel vent systems must be listed as a
UL-1738 approved system for the United
States and a ULC-S636 approved system
for Canada.
Table 2G Stainless Steel Vent Pipe and Fittings
Approved Stainless Steel Vent Manufacturers
Make
Model
Dura Vent (M & G Group)
FasNSeal Vent / FasNSeal Flex* Vent
Z-Flex (Nova Flex Group)
Z-Vent
Heat Fab (Selkirk Corporation)
Saf-T Vent
*Use of FasNSeal Flex smooth inner wall vent is to be used in vertical or near vertical sections only, taking precaution to ensure
no sagging occurs of the vent system. Connect to the FasNSeal rigid vent using specially designed adapters and sealing method,
see manufacturer’s instructions.
Table 2H Approved Stainless Steel (S.S.) Terminations and Adapters
ProTech
Heat Fab
Z Flex
FasNSeal
Saf-T Vent
Z-Vent
Model
Intake
Air
Termination
Intake
Air
S.S.
Flue
S.S.
Flue
S.S.
Flue
Intake Air
Adapter Termination
Adapter Termination
Adapter Termination Termination
Termination
FSBS3
300715
9392
9301PVC
2SVSTP03
2SVSRCX03
303889
9314TERM 2SVSLA03
9414TERM 2SVSLA04
2SVSTEX0390
2SVSTEX0490
SNR150 - SNR200
SNA285 - SNA500
FSRC3(R.C)
5300CI
FSBS4
F303759
FSAIH04
303888
9492
9401PVC
2SVSTP04
2SVSRCX04
FSRC4(R.C.)
5400CI
22
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Installation & Service Manual
3 Sidewall direct venting
Vent/air termination – sidewall
Follow instructions below when
determining vent location to avoid
possibility of severe personal injury,
death, or substantial property damage.
Figure 3-1A PVC/CPVC/Polypropylene Sidewall Termination
ƽ WARNING
of Air and Vent
TO BOILER
INTAKE AIR
CONNECTION
FROM BOILER
VENT PIPE
CONNECTION
A gas vent extending through an exterior
ƽ WARNING
wall shall not terminate adjacent to a wall
12"
or below building extensions such as eaves,
parapets, balconies, or decks. Failure to
comply could result in severe personal
injury, death, or substantial property
damage.
POSSIBLE ORIENTATIONS
MIN
TO
OVER-
HANG
VENT / AIR
TERMINATION
12"
MIN
Determine location
GRADE OR
SNOW LINE
Locate the vent/air terminations using the following
guidelines:
Table 3A Sidewall Vent Kits
1. The total length of piping for vent or air must not exceed
the limits given in the General Venting Section on page 17
of this manual.
Model
Kit Number Vent Size
SNR150-100 -- SNR200-100
SNA285-125 -- SNA500-125
KIT30045
KIT30046
3 inch vent
4 inch vent
2. You must consider the surroundings when terminating
the vent and air:
If using the alternate sidewall termination:
a. Position the vent termination where vapors will
not damage nearby shrubs, plants or air
conditioning equipment or be objectionable.
b. The flue products will form a noticeable plume as
they condense in cold air. Avoid areas where the
plume could obstruct window views.
c. Prevailing winds could cause freezing of
condensate and water/ice buildup where flue
products impinge on building surfaces or plants.
d. Avoid possibility of accidental contact of flue
products with people or pets.
e. Do not locate the terminations where wind eddies
could affect performance or cause recirculation,
such as inside building corners, near adjacent
buildings or surfaces, window wells, stairwells,
alcoves, courtyards, or other recessed areas.
3. The air piping must terminate in a down-turned elbow as
shown in FIG. 3-1B. This arrangement avoids recirculation
of flue products into the combustion air stream.
4. The vent piping must terminate in an elbow pointed
outward or away from the air inlet, as shown in FIG. 3-1B.
Do not exceed the maximum lengths of the
ƽ WARNING
outside vent piping shown in FIG. 3-1B.
Excessive length exposed to the outside could
cause freezing of condensate in the vent pipe,
resulting in potential water heater shutdown.
Figure 3-1B Alternate PVC/CPVC/Polypropylene Sidewall
Termination of Air and Vent w/Field Supplied Fittings
Sidewall vent and air inlet terminations
must terminate in the same pressure
zone.
ƽ WARNING
f. Do not terminate above any door or window.
Condensate can freeze, causing ice formations.
g. Locate or guard vent to prevent condensate damage
to exterior finishes.
23
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Installation & Service Manual
3 Sidewall direct venting
Vent/air termination – sidewall
6. Locate terminations so they are not likely to be damaged
by foreign objects, such as stones or balls, or subject to
buildup of leaves or sediment.
Figure 3-1C Alternate PVC/CPVC/SS/ Polypropylene Venting
Arrangement (if Space Allows) w/Field Supplied Fittings
TO BOILER
COUPLING
INTAKE AIR
CONNECTION
Figure 3-2A Clearance to Gravity Air Inlets
12” MIN
15” MAX
FROM BOILER
VENT PIPE
CONNECTION
BIRD SCREEN
12"
MIN.
12”
MIN
BIRD
SCREEN
GRADE OR
SNOW LINE
ALTERNATE VENTING ARRANGEMENT
(IF SPACE PERMITS)
VENT / AIR
TERMINATION
Figure 3-1D Alternate SS Venting Arrangement -
Typical Stainless Steel Sidewall Termination of Air and
Vent w/Field Supplied Fittings, Utilizing a Hood Intake
12"
MIN.
12"
MIN.
BIRD SCREEN
Figure 3-2B Alternate Clearance to Gravity Air Inlets w/
Field Supplied Fittings
TO BOILER
INTAKE AIR
CONNECTION
12" (305 MM) MIN
15" (381 MM) MAX
FROM BOILER
VENT PIPE
CONNECTION
12”
MIN.
12" (305 MM) MIN
BIRD
SCREEN
(TYPICAL)
GRADE OR
SNOW LINE
5. Maintain clearances as shown in FIG.’s 3-1A thru 3-3B,
pages 23 - 25. Also maintain the following:
a. Vent must terminate:
12”
MIN.
12”
MIN.
• At least 6 feet from adjacent walls.
• No closer than 12 inches below roof overhang.
• At least 7 feet above any public walkway.
• At least 3 feet above any forced air intake within
10 feet.
• No closer than 12 inches below or horizontally
from any door or window or any other gravity air
inlet.
Figure 3-3A Clearance to Forced Air Inlets
IF LESS
THAN 10’
VENT / AIR
TERMINATION
36"
MIN.
b. Air inlet must terminate at least 12 inches above
grade or snow line; at least 12 inches below the vent
termination; and the vent pipe must not extend
more than 24 inches vertically outside the building
as shown in FIG. 3-1B. Condensate could freeze and
block vent pipe.
FORCED AIR
INLET
7' MIN. ABOVE ANY
PUBLIC WALKWAY
c. Do not terminate closer than 4 feet horizontally
from any electric meter, gas meter, regulator, relief
valve, or other equipment. Never terminate above or
below any of these within 4 feet horizontally.
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24
TM
Installation & Service Manual
3 Sidewall direct venting
(continued)
Figure 3-3B Alternate Clearance to Forced Air Inlets w/
Figure 3-4A PVC/CPVC Sidewall Termination Assembly
Field Supplied Fittings
IF LESS
THAN 10’
36”
MIN.
VENT
AIR
FORCED AIR
INLET
CENTERLINE WIDTH
AIR PIPING
BIRD
VENT PIPING
SCREEN
VENT PLATE
VENT CAP
(TYPICAL)
7’ MIN. ABOVE ANY
PUBLIC WALKWAY
WALL PLATE
GALVANIZED
THIMBLE
Prepare wall penetrations
1. Use the factory supplied wall plate as a template to locate
the vent and air intake holes and mounting holes.
Air pipe penetration:
Table 3B Sidewall Vent Centerline Dimensions
Model
Air
Vent Centerline Width
a. Cut a hole for the air pipe. Size the air pipe hole as
close as desired to the air pipe outside diameter.
Vent pipe penetration:
a. Cut a hole for the vent pipe. For either combustible
or noncombustible construction, size the vent pipe
hole with at least a 1/2 inch clearance around the
vent pipe outer diameter:
151 - 200
286
3"
4"
3"
4"
5 5/8"
5 5/8"
Figure 3-4B Polypropylene Sidewall Termination Assembly
SIDEWALL
ADAPTER
• 4½ inch hole for 3 inch vent pipe
• 5½ inch hole for 4 inch vent pipe
(AIR)
WALL
PLATE
Drill 3/16" diameter holes for inserting the plastic anchors
into the wall.
SIDEWALL
RETAINING
PLATE
2. For Polypropylene Only: Install the vent and air intake
sidewall adapters from Table 2F on page 21 into the vent
plate. Slide the sidewall retaining bracket down the
sidewall adapters flush to the vent plate (FIG. 3-4B).
3. For PVC/CPVC Only: Install the vent and air intake
piping through the wall into the vent plate openings.
Use RTV silicone sealant to seal the air pipe. Use the
cement/primer listed in Table 2D on page 20 to seal the
vent pipe.
VENT
PLATE
VENT
CAP
SIDEWALL
ADAPTER
(VENT)
4. Mount and secure the vent plate to the wall, using stainless
steel screws.
5. Seal all gaps between the pipes and wall. Seal around the
plate to the wall assuring no air gaps.
IMG00085
GALVANIZED
THIMBLE
6. Assemble the vent cap to the vent plate (see FIG.'s 3-4A
and 3-4B). Insert the stainless steel screws into the vent
cap screw hole openings and securely attach the vent cap
to the vent plate.
7. Seal all wall cavities.
8. PVC/CPVC terminations are designed to accommodate
any wall thickness of standard constructions per the
directions found in this manual.
9. Stainless steel terminations are designed to penetrate
walls with a thickness up to 9.25 inches of standard
construction.
25
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Installation & Service Manual
3 Sidewall direct venting
Prepare wall penetrations (Alternate -
Field Supplied Option)
Figure 3-5A Multiple Vent Terminations (must also
comply with Figure 3-1A)
1. Air pipe penetration:
12" MIN. BETWEEN EDGE OF AIR
INLET AND ADJACENT VENT OUTLET
a. Cut a hole for the air pipe. Size the air pipe hole as
close as desired to the air pipe outside diameter.
VENT
2. Vent pipe penetration:
AIR
a. Cut a hole for the vent pipe. For either combustible
or noncombustible construction, size the vent pipe
hole with at least a 1/2 inch clearance around the
vent pipe outer diameter:
• 4½ inch hole for 3 inch vent pipe
• 5½ inch hole for 4 inch vent pipe
b. Insert a galvanized metal thimble in the vent pipe
hole as shown in FIG. 3-4C.
3. Use a sidewall termination plate as a template for correct
location of hole centers.
VENT / AIR
TERMINATION
4. Follow all local codes for isolation of vent pipe when
passing through floors or walls.
Figure 3-5B Alternate Multiple Vent Terminations w/Field
Supplied Fittings (must also comply with Figure 3-1B)
5. Seal exterior openings thoroughly with exterior caulk.
Figure 3-4C Alternate Sidewall Termination Assembly
w/Field Supplied Fittings
ELBOW
AIR PIPING
VENT PIPING
BIRD SCREEN
GALVANIZED
THIMBLE
ELBOW
BIRD SCREEN
SIDEWALL
TERMINATION PLATE
Multiple vent/air terminations
1. When terminating multiple Shield water heaters terminate
each vent/air connection as described in this manual
(FIG. 3-5A).
All vent pipes and air inlets must terminate
ƽ WARNING
at the same height to avoid possibility
of severe personal injury, death, or
substantial property damage.
2. Place wall penetrations to obtain minimum clearance
of 12 inches between edge of air inlet and adjacent vent
outlet, as shown in FIG. 3-5A for U.S. installations. For
Canadian installations, provide clearances required by
CSA B149.1 Installation Code.
3. The air inlet of a Shield water heater is part of a direct vent
connection. It is not classified as a forced air intake with
regard to spacing from adjacent water heater vents.
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26
TM
Installation & Service Manual
3 Sidewall direct venting
(continued)
Sidewall termination – optional concentric vent
Description and usage
Lochinvar offers optional concentric combustion air and 3. Cut one (1) hole (5 inch diameter for #CVK3003
vent pipe termination kits (Factory Kit #CVK3003 for 3"
diameter - Models SNR150-100 - SNR200-100 and #CVK3007
for 4" diameter - Models SNA285-125 - SNA500-125). Both
combustion air and vent pipes must attach to the termination
kit. The termination kits must terminate outside the structure
and must be installed as shown in FIG. 3-6.
installations or
installations) into the structure to install the termination
kit.
7
inch diameter for #CVK3007
4. Partially assemble the concentric vent termination kit.
Clean and cement using the procedures found in these
instructions.
The required combustion vent pipe materials are listed in Table
2D, on page 20 of this manual.
a. Cement the Y concentric fitting to the larger kit pipe
(FIG.’s 3-7 and 3-8).
b. Cement the rain cap to the smaller diameter kit pipe
(FIG.’s 3-7 and 3-8).
Figure 3-6 Concentric Sidewall Termination
Figure 3-7 Kit Contents_CVK3003 - SNR150-100 --
SNR200-100
Figure 3-8 Kit Contents_CVK3007 - SNA285-125 --
SNA500-125
Sidewall termination installation
1. Determine the best location for the termination kit (see
FIG. 4-6).
RAIN CAP
2. Reference the Determine Location Section on page 23 of
6" (152 MM) TO 4" (102 MM) REDUCER
6" (152 MM) DIA.
this manual for general termination considerations.
6" (152 MM) DIA.
4" (102 MM) DIA.
"Y" CONCENTRIC
FITTING
6" (152 MM) DIA.
"FLEXIBLE" PIPE
COUPLING
27
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Installation & Service Manual
3 Sidewall direct venting
Sidewall termination – optional concentric vent
Figure 3-9 Concentric Vent Dimensional Drawing -
Figure 3-10 Concentric Vent Dimensional Drawing -
Models SNR150-100 -- SNR200-100 / CVK3003
Models SNA285-125 -- SNA500-125 / CVK3007
"A"
"B" DIA.
"C" DIA.
"D"
3"
(76 MM)
"E"
"G"
"H" DIA.
"B" DIA. PVC
VENT / EXHAUST
"F"
6. Install the Y concentric fitting and pipe assembly through
the structure’s hole.
Instead of cementing the smaller pipe
NOTICE
to the rain cap, a field-supplied stainless
steel screw may be used to secure the
two (2) components together when
field disassembly is desired for cleaning
(see FIG. 3-11).
Do not allow insulation or other materials to
accumulate inside the pipe assembly when
installing through the hole.
NOTICE
7. Install the rain cap and small diameter pipe assembly into
the Y concentric fitting and large pipe assembly. Ensure
small diameter pipe is bottomed and cemented in the Y
concentric fitting for #CVK3003 installations and fastened
tightly into the rubber adapter for #CVK3007 installations.
When using the alternate screw assembly
method, drill a clearance hole in the rain
ƽ WARNING
cap and a pilot hole in the vent pipe
for the screw size being used. Failure to
drill adequate holes may cause cracking of
PVC components, allowing combustion
products to be recirculated. Failure to
follow this warning could result in personal
injury or death.
8. Secure the assembly to the structure as shown in FIG. 3-12
using field-supplied metal strapping or equivalent support
material.
Ensure termination location clearance
NOTICE
Do not operate the appliance with
ƽ WARNING
dimensions are as shown in FIG. 3-6.
the rain cap removed or recirculation
of combustion products may occur.
Water may also collect inside the larger
combustion air pipe and flow to the
burner enclosure. Failure to follow this
warning could result in product damage
or improper operation, personal injury,
or death.
If assembly needs to be extended to allow
NOTICE
sidewall thickness requirement, the two (2)
pipes supplied in the kit may be replaced
by using the same diameter, field-supplied
SDR-26 PVC (D2241) pipe for CVK3003
and standard schedule 40 PVC for CVK3007.
Do not extend dimension D* more than 60
inches (see FIG.’s 3-9 and 3-10).
Figure 3-11 Rain Cap to Vent Pipe Alternate Assembly
If assembly depth needs to be reduced,
NOTICE
dimension D can be as short as possible.
28
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TM
Installation & Service Manual
3 Sidewall direct venting
(continued)
Sidewall termination – optional concentric vent
Figure 3-12 Concentric Vent Sidewall Attachment
Note: CVK3003 shown for illustration purposes.
Multiventing sidewall terminations
DO NOT use field-supplied couplings
to extend pipes. Airflow restriction
will occur and may cause intermittent
operation.
CAUTION
When two (2) or more direct vent appliances are vented
near each other, each appliance must be individually vented
(see FIG. 3-13). NEVER common vent or breach vent this
appliance. When two (2) or more direct vent appliances are
vented near each other, two (2) vent terminations may be
installed as shown in FIG. 3-13. The vent terminations must
be at least 36 inches away from the first two (2) terminations. It
is important that vent terminations be made as shown to avoid
recirculation of flue gases. Dimension A in FIG. 3-13 represents
the distance between pipes or rain shields, as touching or a 2
inch maximum separation.
9. Cement appliance combustion air and vent pipes to the
concentric vent termination assembly. See FIG. 3-12 for
proper pipe attachment.
10. Operate the appliance one (1) heat cycle to ensure
combustion air and vent pipes are properly connected
to the concentric vent termination connections.
Figure 3-13 Concentric Vent and Combustion Air Termination Dimension A as
Touching or 2 inches Maximum Separation
29
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Installation & Service Manual
4 Vertical direct venting
Vent/air termination – vertical
Followinstructionsbelowwhendetermining
vent location to avoid possibility of severe
personal injury, death or substantial
property damage.
Rooftop vent and air inlet terminations
must terminate in the same pressure zone,
unless vertical vent sidewall air is set up as
shown in the General Venting - Vertical
Vent, Sidewall Air Section.
ƽ WARNING
ƽ WARNING
Determine location
Locate the vent/air terminations using the following
Figure 4-1A Vertical Termination of Air and Vent
guidelines:
1. The total length of piping for vent or air must not exceed
the limits given in the General Venting Section on page
17 of this manual.
2. Prepare the vent termination and the air termination
elbow (FIG. 4-1A) by inserting bird screens. Bird screens
should be obtained locally.
3. The vent must terminate at least 3 feet above the highest
place in which the vent penetrates the roof and at least
2 feet above any part of a building within 10 horizontal
feet.
4. The air piping must terminate in a down-turned 180°
return pipe no further than 2 feet from the center of the
vent pipe. This placement avoids recirculation of flue
products into the combustion air stream.
Figure 4-1B Stainless Steel Vertical Termination of Air
and Vent
5. The vent piping must terminate in an up-turned coupling
as shown in FIG. 4-1A. The top of the coupling must
be at least 1 foot above the air intake. When the vent
termination uses a rain cap as illustrated in FIG. 4-1B
maintain at least 36" (914 mm) above the air inlet. The
air inlet pipe and vent pipe can be located in any desired
position on the roof, but must always be no further than
2 feet (.6 m) apart and with the vent termination at least
1 foot for PVC and 3 feet for stainless steel, above the air
intake.
ALTERNATE INTAKE LOCATIONS:
INTAKE PIPES MAY BE LOCATED
ANYWHERE WITHIN 24” (610 MM)
OF VENT PIPE
BIRD SCREEN
VENT
(TYPICAL)
6" (152 MM) MINIMUM
ABOVE ROOF /
SNOW LINE
6. Maintain the required dimensions of the finished
termination piping as shown in FIG. 4-1A.
COM,BUSTION
AIR
VENT OUTLET
36” (914 MM) MINIMUM
ABOVE AIR INLET
7. Do not extend exposed vent pipe outside of building
more than shown in this document. Condensate could
freeze and block vent pipe.
8. Locate terminations so they are not likely to be damaged by
foreign objects, such as stones or balls, or subject to buildup
of leaves or sediment.
30
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Installation & Service Manual
4 Vertical direct venting
(continued)
Vent/air termination – vertical
Prepare roof penetrations
Figure 4-2 Vertical Terminations with Multiple Water
1. Air pipe penetration:
Heaters
a. Cut a hole for the air pipe. Size the air pipe hole as
close as desired to the air pipe outside diameter.
2. Vent pipe penetration:
a. Cut
a
hole for the vent pipe.
For either
combustible or noncombustible construction, size
the vent pipe hole with at least a 1/2 inch clearance
around the vent pipe outer diameter:
• 4½ inch hole for 3 inch vent pipe
• 5½ inch hole for 4 inch vent pipe
b. Insert a galvanized metal thimble in the vent pipe
hole.
3. Space the air and vent holes to provide the minimum
spacing shown in FIG. 4-1A, page 30.
Figure 4-3 Alternate Vertical Terminations with Multiple
Water Heaters
4. Follow all local codes for isolation of vent pipe when passing
through floors, ceilings, and roofs.
5. Provide flashing and sealing boots sized for the vent pipe
and air pipe.
Multiple vent/air terminations
1. When terminating multiple Shield water heaters, terminate
each vent/air connection as described in this manual (FIG.
4-2).
Terminate all vent pipes at the same height
ƽ WARNING
and all air pipes at the same height to avoid
possibility of severe personal injury, death,
or substantial property damage.
2. Place roof penetrations to obtain minimum clearance of
12 inches between edge of air intake elbow and adjacent
vent pipe of another water heater for U.S. installations (see
FIG. 4-2). For Canadian installations, provide clearances
required by CSA B149.1 Installation Code.
3. The air inlet of a Shield water heater is part of a direct
vent connection. It is not classified as a forced air intake
with regard to spacing from adjacent water heater vents.
31
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Installation & Service Manual
4 Vertical direct venting
Vertical termination – optional concentric vent
Description and usage
2. Cut one (1) hole (5 inch diameter for #CVK3003 installations
or 7 inch diameter for #CVK3007 installations) into the
structure to install the termination kit.
3. Partially assemble the concentric vent termination kit.
Clean and cement following the cleaning procedures in
these instructions.
Lochinvar offers an optional concentric combustion air and
vent pipe termination kit. Both combustion air and vent
pipes must attach to the termination kit. The termination kit
must terminate outside the structure and must be installed as
shown in FIG. 4-4.
Field supplied pipe and fittings are required to complete the
installation.
The required combustion air and vent pipe fittings are listed
in Table 2D, on page 20 of this manual.
a. Cement the Y concentric fitting to the larger diameter
kit pipe (see FIG.’s 3-7 and 3-8, page 27).
b. Cement rain cap to the smaller diameter kit pipe
(see FIG.’s 3-7 and 3-8, page 27).
c. Do not attach a U-Bent to the rain cap. Doing so could
cause recirculation (see FIG. 4-5).
Vertical termination installation
1. See Section 4, Vertical Direct Venting - Determine
Location (where applicable).
Instead of cementing the smaller pipe to
NOTICE
the rain cap, a field supplied stainless steel
Figure 4-4 Concentric Vertical Termination
screw may be used to secure the two (2)
components together when field disassembly
is desired for cleaning (see FIG. 3-11, page 28).
When using the alternate screw assembly
ƽ WARNING
method, drill a clearance hole in the rain
cap and a pilot hole in the vent pipe for
the screw size being used. Failure to drill
adequate holes may cause cracking of PVC
components, allowing combustion products
to be recirculated. Failure to follow this
warning could result in personal injury or
death.
Figure 4-5 Do Not Install U-Bent to Rain Cap
32
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Installation & Service Manual
4 Vertical direct venting
(continued)
Vertical termination – optional concentric vent
Do not operate the appliance with
DO NOT use field-supplied couplings
to extend pipes. Airflow restriction will
occur.
CAUTION
ƽ WARNING
the rain cap removed or recirculation
of combustion products may occur.
Water may also collect inside the larger
combustion air pipe and flow to the
burner enclosure. Failure to follow this
warning could result in product damage
or improper operation, personal injury,
or death.
6. Install the rain cap and the small diameter pipe
assembly into the roof penetration assembly. Ensure
the small diameter pipe is cemented and bottomed in
the Y concentric fitting for #CVK3003 installations and
fastened tightly into the rubber adapter for #CVK3007
installations.
4. Install the Y concentric fitting pipe assembly up through
the structure’s hole and field supplied roof boot/flashing.
7. Cement the appliance combustion air and vent pipes to
the concentric vent termination assembly. See FIG. 4-6
for proper pipe attachment.
Do not allow insulation or other materials
NOTICE
to accumulate inside the pipe assembly
8. Operate the appliance through one (1) heat cycle to ensure
combustion air and vent pipes are properly connected to
the concentric vent termination connections.
when installing through the hole.
5. Secure the assembly to the roof structure as shown
below in FIG. 4-6 using field supplied metal strapping or
equivalent support material.
Multiventing vertical terminations
Figure 4-6 Concentric Vent Roof Installation
When two (2) or more direct vent appliances are vented
near each other, each appliance must be individually vented
(see FIG. 4-7). NEVER common vent or breach vent this
appliance. When two (2) or more direct vent appliances
are vented near each other, two (2) vent terminations may
be installed as shown in FIG. 4-7. The vent terminations
must be at least 36 inches away from the first two (2)
terminations. It is important that vent terminations be made
as shown to avoid recirculation of flue gases. Dimension A in
FIG. 4-7 represents the distance between pipes or rain shields,
as touching or a 2 inch maximum separation.
Note: CVK3003 shown for illustration purposes.
Figure 4-7 Concentric Vent and Combustion Air Vertical
Termination (Dimension A as Touching or
Maximum Separation)
2 inches
Ensure termination height is above the
NOTICE
roof surface or anticipated snow level
(12 inches in U.S.A. or 18 inches in
Canada) as shown in FIG. 4-4, page 32.
If assembly is too short to meet height
NOTICE
requirement, the two (2) pipes supplied
in the kit may be replaced by using
the same diameter, field supplied SDR-
26 PVC (D2241) pipe for #CVK3003
and standard schedule 40 PVC for
#CVK3007. Do not extend dimension
D* more than 60 inches (see FIG.’s 3-9
and 3-10, page 28).
33
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Installation & Service Manual
5 System piping
System water piping methods
2. If this water heater is installed in a closed water supply
system, such as the one having a backflow preventer in
the cold water supply, provisions must be made to control
thermal expansion. DO NOT operate this water heater in
a closed system without provisions for controlling thermal
expansion. Warranties do not cover damages from thermal
expansion such as pressure bulges and/or deformities.
Your water supplier or local plumbing inspector should be
contacted on how to control this situation.
Observe a minimum of one inch clearance around all
un-insulated hot water pipes when openings around the pipes
are not protected by non-combustible materials.
Failure to install and maintain a new,
ƽ WARNING
listed temperature and pressure relief valve
will release the manufacturer from any
claim, which might result from excessive
temperature and pressures.
3. After installation of the water lines, open the main water
supply valve and fill the water heater. While the water
heater is filling, open several hot water faucets to allow air
to escape from the water system. When a steady stream of
water flows through the faucets, close them and check all
water connections for possible leaks.
Keep clear of the combination temperature
and pressure relief valve discharge line
outlet. The discharge may be hot enough
to cause scald injury. The water is under
pressure and may splash.
Hydrogen gas can be produced in an
operating water heater that has not
had water drawn from the tank for a
long period of time (generally two
weeks or more). HYDROGEN GAS IS
EXTREMELY FLAMMABLE. To prevent
the possibility of injury under these
conditions, we recommend the hot water
faucet to be open for several minutes at the
kitchen sink before you use any electrical
appliance, which is connected to the hot
water system. If hydrogen is present, there
will be an unusual sound such as air
escaping through the pipes as hot water
begins to flow. Do not smoke or have an
open flame near the faucet at the time it
is open.
4. Never operate the water heater without first being certain it
is filled with water.
Scalding
This water heater can deliver scalding temperature water at any
faucet in the system. Be careful whenever using hot water to
avoid scalding injury. Certain appliances such as dishwashers
and automatic clothes washers may require increased
temperature water. By setting the thermostat on this water
heater to obtain the increased temperature water required by
these appliances, you may create the potential for scald injury.
To protect against injury, you should install an ASSE approved
mixing valve in the water system. This valve will reduce point of
discharge temperature by mixing cold and hot water in branch
supply lines. Such valves are available from the local plumbing
supplier.
Figure 5-1 Scald Warning
General piping information
Basic steps are listed below along with illustrations on the
following pages (FIG.’s 5-2 thru 5-4), which will guide you
through the installation of the Shield water heater.
1. BEFORE PROCEEDING WITH THE INSTALLATION,
CLOSE THE MAIN WATER SUPPLY VALVE. After
shutting off the main water supply, open a faucet to
relieve the water line pressure to prevent any water
from leaking out of the pipes while making the water
connections to the water heater. The COLD water inlet
and HOT water outlet are identified on the water heater.
Make the proper plumbing connections between the
water heater and the plumbing system to the building.
Install a shutoff valve in the cold water supply line.
Water temperatures over 125°F (52°C) can cause severe
burns instantly or death from scalds.
Children, disabled, and elderly are at highest risk of being scalded.
See instruction manual before setting the thermostat at the
water heater.
Feel water before bathing or showering.
Temperature limiting valves are available, consult local plumbing
supplier.
34
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Installation & Service Manual
5 System piping
(continued)
Piping components
The following chart (Table 5A) details the relationship of
water temperature and time with regard to scald injury
and may be used as a guide in determining the safest water
temperature for your applications.
Check valves:
Field supplied. Check valves are recommended for installation
as shown in FIG.’s 5-2 thru 5-4.
Table 5A Approximate Time / Temperature Scald Chart
Water heater isolation valves:
APPROXIMATE TIME / TEMPERATURE
RELATIONSHIPS IN SCALDS
Field supplied. Full port ball valves are required. Failure to
use full port ball valves could result in a restricted flow rate
through the water heater.
120°F
125°F
130°F
135°F
140°F
145°F
150°F
155°F
More than 5 minutes
1 1/2 to 2 minutes
About 30 seconds
About 10 seconds
Less than 5 seconds
Less than 3 seconds
About 1 1/2 seconds
About 1 second
Anti-scald mixing valve:
Field supplied. An anti-scald mixing valve is recommended
when storing domestic hot water above 115°F.
Unions:
Field supplied. Recommended for unit serviceability.
Temperature and pressure relief valve:
Factory supplied on water heaters. The temperature and
pressure relief valve is sized to ASME specifications.
Water chemistry
The Shield water heater is designed for
heating potable water with a hardness
of 5 to 25 grains per gallon and a total
dissolved solids not exceeding 350 ppm.
No valves shall be placed between the relief
ƽ CAUTION
NOTICE
valve, heat exchanger, or tank. The relief
valve shall be piped to a suitable drain
as close as possible to the heater with no
reducing couplings or other restrictions.
The piping must be sloping away from the
heater at all times.
The water must be treated if it is not between 5 to 25 grains
per gallon or above 350 ppm of total dissolved solids.
Hardness exceeding 25 grains or 350 ppm can cause non-
warrantable premature failure of the heat exchanger. Water
with a hardness of less than 5 grains per gallon will usually
have a pH which can be aggressive and corrosive causing
non-warrantable damage to the pump and associated piping.
Corrosion due to water chemistry generally shows up first in
the hot water system because heated water increases the rate
of corrosive chemical reactions.
The heater is equipped with 3/4" CPVC
(SDR11) pipe and elbow connections. If
local codes prohibit the use of CPVC, the
CPVC pipe, elbow, and 3/4" NPT adapter
can be replaced with a copper equivalent.
See the * piping illustrations included in this section,
FIG.’s 5-2 thru 5-4 for suggested guidelines in piping the
Shield water heater.
*Please note that these illustrations are
NOTICE
meant to show system piping concept
only, the installer is responsible for all
equipment and detailing required by local
codes.
35
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Installation & Service Manual
5 System piping
Figure 5-2 Single Unit
MIXING VALVE
(IF REQUIRED, SEE PG. 35)
FLOW CHECK
VALVE (TYPICAL)
COLD WATER
SUPPLY
BUILDING
RETURN
SYSTEM
CIRCULATOR
HOT WATER
SUPPLY
EXPANSION
TANK
BALL VALVE
(TYPICAL)
UNION
(TYPICAL)
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
NOTICE
36
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Installation & Service Manual
5 System piping
(continued)
Figure 5-3 Multiple Units
FLOW CHECK
COLD WATER
SUPPLY
VALVE (TYPICAL)
BUILDING
RETURN
UNION
(TYPICAL)
SYSTEM
CIRCULATOR
EXPANSION
TANK
BALL VALVE
(TYPICAL)
HOT WATER
SUPPLY
MIXING VALVE
(IF REQUIRED, SEE PG. 35)
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
NOTICE
37
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Installation & Service Manual
5 System piping
Figure 5-4 Two Temperature - Single Unit
FLOW CHECK
VALVE (TYPICAL)
THERMOMETER
(TYPICAL)
180°HOT
WATER
SUPPLY
MIXING
VALVE
140°HOT
WATER
SUPPLY
COLD
WATER
SUPPLY
LOW TEMPERATURE
BUILDING RETURN
BALL
EXPANSION
TANK
UNION
(TYPICAL)
VALVE
(TYPICAL)
HIGH TEMPERATURE
BUILDING RETURN
Please note that these illustrations are meant to show system piping concept only, the installer is responsible
for all equipment and detailing required by local codes.
NOTICE
38
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Installation & Service Manual
6 Gas connections
Connecting gas supply piping
1. Install ground joint union for servicing, when 4. Support piping with hangers, not by the water heater or its
required.
accessories.
The gas valve and blower will not support
the weight of the piping. Do not attempt to
support the weight of the piping with the
water heater or its accessories. Failure to
comply could result in severe personal injury,
death, or substantial property damage.
2. On Models SNR150-100 -- SNA285-125 install a manual
shutoff valve in the gas supply piping outside water heater
jacketwhenrequiredbylocalcodesorutilityrequirements.
ƽ WARNING
3. In Canada – When using manual main shutoff valves, it
must be identified by the installer.
5. Purge all air from the gas supply piping.
Figure 6-1 Gas Supply Piping - Models SNR150-100
-- SNA285-125
6. Before placing the water heater in operation, check the
water heater and its gas connection for leaks.
a. The appliance must be disconnected from the gas
supply piping system during any pressure testing of
that system at a test pressure in excess of 1/2 PSIG
(3.5 kPa).
GAS SUPPLY
b. The appliance must be isolated from the gas supply
piping system by closing a manual shutoff valve
during any pressure testing of the gas supply piping
system at test pressures equal to or less than 1/2 PSIG
(3.5 kPa).
UNION
DRIP LEG
MANUAL GAS
SHUT OFF VALVE
(FIELD SUPPLIED)
c. The appliance and its gas connection must be leak
tested before placing it in operation.
Do not check for gas leaks with an open
ƽ WARNING
flame – use the bubble test. Failure to use the
bubble test or check for gas leaks can cause
severe personal injury, death, or substantial
property damage.
Figure 6-2 Gas Supply Piping - Models SNA400-125
-- SNA500-125
7. Use pipe sealing compound compatible with propane gases.
Apply sparingly only to male threads of the pipe joints so
that pipe dope does not block gas flow.
MANUAL GAS
SHUTOFF VALVE
(FACTORY SUPPLIED ON
MODELS SNA400-125 --
SNA500-125)
GAS SUPPLY
DRIP LEG
UNION
39
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6 Gas connections
Failure to apply pipe sealing compound as
Natural gas:
ƽ WARNING
detailed in this manual can result in severe
personal injury, death, or substantial
property damage.
Pipe sizing for natural gas
1. Refer to Table 6A for pipe length and diameter. Based on
rated water heater input (divide by 1,000 to obtain cubic
feet per hour).
Shield water heaters are typically shipped
ready to fire on natural gas. Check the
water heater rating plate to determine
which fuel the water heater is set for. In
order to operate on LP gas contact the
factory, an orifice MUST BE installed or
a gas valve adjustment MUST BE made.
Failure to comply could result in severe
personal injury, death, or substantial
property damage.
ƽ WARNING
a. Table 6A is only for natural gas with specific gravity
0.60 inches, with a pressure drop through the gas
piping of 0.50 inches w.c.
b. For additional gas pipe sizing information, refer to
ANSI Z223.1 (or B149.1 for Canadian installations).
Natural gas supply pressure requirements
1. Pressure required at the gas valve inlet pressure port:
• Maximum 14 inches w.c. with no flow (lockup) or
with water heater on.
Use two wrenches when tightening gas
piping at water heater (FIG. 6-3), using
one wrench to prevent the water heater
gas line connection from turning. Failure
to support the water heater gas connection
pipe to prevent it from turning could
damage gas line components.
ƽ WARNING
• Minimum 4 inches w.c. with gas flowing (verify during
water heater startup).
2. Install 100% lockup gas pressure regulator in supply line if
inlet pressure can exceed 14 inches w.c. at any time. Adjust
lockup regulator for 14 inches w.c. maximum.
Figure 6-3 Inlet Pipe with Backup Wrench
Propane gas:
Shield water heaters are typically shipped
ƽ WARNING
ready to fire on natural gas. Check water
heater rating plate to determine which fuel
the water heater is set for. In order to operate
on LP gas contact the factory, an orifice
MUST BE installed or a gas valve adjustment
MUST BE made. Failure to comply could
result in severe personal injury, death, or
substantial property damage.
Pipe sizing for propane gas
1. Contact gas supplier to size pipes, tanks, and 100% lockup
gas pressure regulator.
Propane Supply Pressure Requirements
USE BACK UP WRENCH
TO PREVENT PIPE FROM
ROTATING
1. Adjust propane supply regulator provided by the gas
supplier for 14 inches w.c. maximum pressure.
Maximum inlet gas pressure must not
2. Pressure required at gas valve inlet pressure port:
• Maximum 14 inches w.c. with no flow (lockup) or with
water heater on.
NOTICE
exceed the value specified. Minimum
value listed is for the purposes of input
adjustment.
• Minimum 8 inches w.c. with gas flowing (verify during
water heater startup).
Ensure that the high gas pressure
regulator is at least 10 feet upstream of
the appliance.
ƽ WARNING
40
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Installation & Service Manual
6 Gas connections
(continued)
Table 6A Natural Gas Pipe Size Chart
Natural Gas Pipe Capacity Chart
Length of Pipe in Straight Feet for 1/2 PSI
Nominal
Iron Pipe
Size (Inches)
10
175
20
30
97
40
82
50
60
70
80
N/A
90
N/A
100
N/A
125
N/A
150
N/A
175
N/A
200
N/A
1/2
3/4
1
120
256
477
974
N/A
155
292
595
923
N/A
141
267
543
830
N/A
128
246
502
769
369
205
384
789
174
328
677
121
113
106
95
86
79
74
697
236
210
200
179
164
333
513
974
1540
2720
5640
149
308
472
871
1400
2500
5130
138
287
441
820
1300
2340
4720
1-1/4
1-1/2
2
1400
2150
4100
6460
472
441
410
369
1500 1210 1020
707
666
636
564
2820 2260 1950 1720 1560 1440
4460 3610 3100 2720 2460 2310
1330
2100
3800
7690
1250
2000
3540
7380
1180
1900
3330
6870
1100
1700
3000
6150
2-1/2
3
11200 7900 6400 5400 4870 4410 4000
23500 16100 13100 11100 10000 9000 8300
4
Shield water heaters are typically shipped ready to fire on natural gas. Check the water heater rating plate to
determine which fuel the water heater is set for. In order to operate on LP gas contact the factory, an orifice
MUST BE installed or a gas valve adjustment MUST BE made. Failure to comply could result in severe
personal injury, death, or substantial property damage.
ƽ WARNING
5. Reconnect power to the appliance.
Check inlet gas supply
CSA or UL listed flexible gas connections
6. Adjust the temperature set point on the control panel of
the electronic control module to call for heat.
NOTICE
are acceptable, but you must exercise
caution to ensure that the line has adequate
capacity to allow your water heater to fire
at full rate. Consult with local codes for
proper installation or service procedures.
7. Observe the gas supply pressure as the burner fires at
100% of rated input. Percent of burner input will be
displayed on the control panel.
8. Ensure inlet pressure is within specified range.
Minimum and maximum gas supply pressures are
specified in this section of the manual.
DO NOT adjust or attempt to measure
gas valve outlet pressure. The gas valve is
factory-set for the correct outlet pressure.
This setting is suitable for natural gas
and propane (when configured for LP),
requiring no field adjustment. Attempting
to alter or measure the gas valve outlet
pressure could result in damage to the
valve, causing potential severe personal
injury, death, or substantial property
damage.
ƽ WARNING
9. If gas supply pressure is within normal range and no
adjustments are needed, proceed on to Step 11.
10. If the gas pressure is out of range, contact the gas utility,
gas supplier, qualified installer or service agency to
determine the necessary steps to provide proper gas
pressure to the control.
11. Disconnect power from the appliance.
12. Shut off the gas to the appliance.
The gas piping must be sized for the proper flow and length
of pipe, to avoid excessive pressure drop. Both the gas meter
and the gas regulator must be properly sized for the total gas
load.
13. Remove the manometer from the pressure tap on top of
the gas valve. Re-tighten the set screw inside the pressure
tap.
When re-tightening the set screw, be sure to
tighten securely to prevent gas leaks.
If you experience a pressure drop greater than 1 inch w.c.,
the meter, regulator, or gas line is undersized or in need of
service. Perform the steps below when checking inlet gas
supply:
ƽ WARNING
Do not check for gas leaks with an open
flame -- use the bubble test. Failure to
use the bubble test or check for gas leaks
can cause severe personal injury, death, or
substantial property damage.
1. Disconnect power from the appliance.
2. Shut off gas to the appliance.
14. Reconnect gas to the appliance.
15. Reconnect power to the appliance.
3. Loosen the set screw one (1) full turn from inside the
pressure tap on top of the gas valve. Place the tubing of
the manometer over the tap once the set screw is
loosened as shown in FIG.’s 6-4 thru 6-6.
16. Adjust the temperature set point on the control panel of
the electronic control module to the desired water
temperature so the appliance will call for heat.
4. Slowly turn on the gas supply at the field installed
manual gas valve.
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Installation & Service Manual
6 Gas connections
Gas pressure
17. Check burner performance by cycling the system while
you observe burner response. The burner should ignite
promptly. Flame pattern should be stable. Turn system
off and allow burner to cool, then cycle burner again to
ensure proper ignition and flame characteristics.
The gas pressure must remain between 4 inches w.c. (natural),
8 inches w.c. (LP) minimum and 14 inches w.c. (natural and
LP) maximum during stand-by (static) mode and while in
operating (dynamic) mode. If an in-line regulator is used, it
must be a minimum of 10 feet from the Shield water heater.
It is very important that the gas line is properly purged by the
gas supplier or utility company. Failure to properly purge the
lines or improper line sizing, will result in ignition failure.
Figure 6-4 Inlet Gas Supply Check - Models SNR150/100
-- SNA285-125
LOOSEN THE SET SCREW ONE (1) FULL TURN AND
PLACE THE MANOMETER TUBING OVER THE
PRESSURE TAP
The problem is especially noticeable in NEW LP installations
and also in empty tank situations. This can also occur when
a utility company shuts off service to an area to provide
maintenance to their lines.
Gas valve replacement
The gas valve MUST NOT be replaced with a conventional
gas valve under any circumstances. As an additional safety
feature, this gas valve has a flanged connection to the venturi
and blower.
DETAIL
Failure to follow all precautions could
result in fire, explosion, or death!
ƽ WARNING
Figure 6-5 Inlet Gas Supply Check - Model SNA400/125
DO NOT adjust or attempt to measure
ƽ WARNING
LOOSEN THE SET SCREW ONE (1) FULL TURN AND
PLACE THE MANOMETER TUBING OVER THE
PRESSURE TAP
gas valve outlet pressure. The gas valve is
factory-set for the correct outlet pressure.
This setting is suitable for natural gas
and propane (when configured for LP),
requiring no field adjustment. Attempting
to alter or measure the gas valve outlet
pressure could result in damage to the
valve, causing potential severe personal
injury, death, or substantial property
damage.
DETAIL
Figure 6-6 Inlet Gas Supply Check - Model SNA500/125
LOOSEN THE SET SCREW ONE (1) FULL TURN AND
PLACE THE MANOMETER TUBING OVER THE
PRESSURE TAP
DETAIL
42
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7 Field wiring
ELECTRICAL SHOCK HAZARD – For
Installation must comply with:
ƽ WARNING
your safety, turn off electrical power supply
before making any electrical connections
to avoid possible electric shock hazard.
Failure to do so can cause severe personal
injury or death.
1. National Electrical Code and any other national, state,
provincial, or local codes, or regulations.
2. In Canada, CSA C22.1 Canadian Electrical Code Part 1, and
any local codes.
Wiring must be N.E.C. Class 1.
NOTICE
Power cord connection
If original wiring as supplied with the
water heater must be replaced, use only
type 105°C wire or equivalent.
This water heater is designed to operate with 120 VAC and 60
Hz power supply. If allowed by local codes, connect the power
cord provided with the heater to a GFI protected outlet on a
separate circuit and breaker (15 amp recommended). Ensure
the circuit cannot be interrupted by a switch used to control
lights or other appliances.
The water heater must be electrically
grounded as required by National
Electrical Code ANSI/NFPA 70 – latest
edition.
If local codes do not allow for the use of the power cord, remove
the cord from the junction box found on the side of the control
support bracket (FIG. 7-2) and attach conduit to the junction
box. Route the wires out of the appliance to a GFI protected
outlet on a separate circuit and breaker (15 amp recommended).
Label all wires prior to disconnection
when servicing controls. Wiring errors can
cause improper and dangerous operation.
ƽ CAUTION
Low voltage connections
Use of an extension cord is NOT allowed. If
ƽ WARNING
1. Route all low voltage wires through the knockouts in the
rear of the water heater, as shown in FIG. 7-1.
a suitable electrical outlet is not within reach
of the supplied power cord, a new receptacle
must be installed or the power cord must
be replaced with hard conduit as described
above.
2. Connect low voltage wiring to low voltage connection
board as shown in FIG. 7-3 on page 44 of this manual and
the water heater wiring diagram.
Figure 7-2 Remove Power Cable
Figure 7-1 Routing Field Wiring
JUNCTION BOX
LOW VOLTAGE
WIRING KNOCKOUTS
Runtime contacts
The electronic control closes a set of dry contacts whenever the
burnerisrunning. ThisistypicallyusedbyBuildingManagement
Systems to verify that the water heater is responding to a call for
heat.
Auxiliary device proving switch
Alarm contacts
1. When the operation of an external limit needs to be
verified before the water heater fires, remove the jumper
wire from terminals X & B and connect them to the
contacts on the external limit (FIG. 7-3).
The electronic control closes another set of contacts whenever
the water heater is locked out or the power is turned off.
This can be used to turn on an alarm, or signal a Building
Management System that the water heater is down. Note that
the alarm contacts will close momentarily after each call for
heat.
43
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7 Field wiring
Figure 7-3 Low Voltage Field Wiring Connections
44
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7 Field wiring
(continued)
Figure 7-4 Control Inputs/Outputs
LOW VOLTAGE
CONNECTION
BOARD
INPUTS
OUTPUTS
45
TANK SENSOR
LOW WATER CUTOFF
INLET TEMPERATURE
SENSOR
OUTLET TEMPERATURE /
HIGH LIMIT SENSOR
FLUE GAS SENSOR
BLOCKED AIR INLET PRESSURE SWITCH
FLAME SENSOR
BLOCKED DRAIN SWITCH
CONTROL BOARD
DISPLAY PANEL
ALARM BELL (ALARM CONTACTS)
RUNTIME CONTACTS
LOW VOLTAGE
CONNECTION
BOARD
WHR PUMP
IGNITER
BLOWER
CONTROL BOARD
GAS VALVE
DISPLAY PANEL
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8 Condensate disposal
Condensate drain
1. This water heater is a high efficiency appliance that
produces condensate.
To allow for proper drainage on large
horizontal runs, a second line vent may
be required and tubing size may need to
increase to 1 inch.
NOTICE
2. Slope condensate tubing down and away from the
water heater into a drain or condensate neutralizing
filter. Condensate from the Shield water heater will be
slightly acidic (typically with a pH from 3 to 5). Install a
neutralizing filter if required by local codes.
The condensate line must remain
unobstructed, allowing free flow of
condensate. If condensate is allowed to
freeze in the line or if the line is obstructed
in any other manner, condensate can exit
from the water heater tee, resulting in
potential water damage to property.
A
Neutralizer Kit is available from the factory
(KIT3087).
Note: The Neutralizer Kit MUST BE installed horizontally.
5. A condensate removal pump is required if the water heater
is below the drain. When installing a condensate pump,
select one approved for use with condensing water heaters
and furnaces. The pump should have an overflow switch
to prevent property damage from condensate spillage. The
switch should be wired to the auxiliary device proving
switch terminals on the low voltage connection board.
3. Leave the top of the 1/2 inch tee OPEN (FIG. 8-1). This
is needed as a vacuum break.
4. Do not expose condensate line to freezing temperatures.
Use materials approved by the authority
NOTICE
having jurisdiction. In the absence of
other authority, PVC and CPVC pipe
must comply with ASTM D1785 or
D2845. Cement and primer must comply
with ASME D2564 or F493. For Canada
use CSA or ULC certified PVC or CPVC
pipe, fittings, and cement.
Figure 8-1 Condensate Disposal
1/2” (12.7 mm) PVC TEE ASSEMBLY
(FACTORY SUPPLIED)
Note: The Neutralizer Kit MUST BE installed horizontally.
NEUTRALIZER KIT
FLOOR DRAIN OR
DRAIN PAN
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9 Start-up
Chlorine concentration less than 200 ppm
Propane water heaters only – Your propane
supplier mixes an odorant with the propane
to make its presence detectable. In some
instances, the odorant can fade, and the gas
may no longer have an odor. Before startup
(and periodically thereafter), have the
propane supplier verify the correct odorant
level in the gas.
ƽ WARNING
1. Do not fill the water heater or operate with water
containing chlorine in excess of 200 ppm.
2. Filling with chlorinated fresh water should be acceptable
since drinking water chlorine levels are much lower.
3. Do not use the water heater to directly heat swimming
pool or spa water.
Inspect/fill condensate system
4. At initial fill and during water heater startup and testing,
check system thoroughly for any leaks. Repair all leaks
before proceeding further.
Inspect/check condensate lines and fittings
1. Inspect the condensate drain line, condensate PVC fittings
and condensate trap.
Check for gas leaks
Fill condensate trap with water
1. Remove the PVC cap retaining screw from the PVC cap
(FIG. 9-1).
Before starting the water heater, and
ƽ WARNING
during initial operation, smell near
the floor and around the water heater
for gas odorant or any unusual odor.
Remove the top access panel and smell
the interior of the water heater enclosure.
Do not proceed with startup if there is any
indication of a gas leak. Use an approved
leak detection solution. Repair any leaks
at once.
2. Remove the 2 inch PVC cap with the switch located at the
top of the trap (FIG. 9-1).
3. Fill with fresh water until the water begins to pour out of
the drain.
4. Replace the cap. Press the cap onto the trap until the cap
makes contact with the drain.
5. Replace the retaining screw.
DO NOT adjust or attempt to measure
ƽ WARNING
The condensate trap (FIG. 9-1) must be filled
with water during all times of water heater
ƽ WARNING
gas valve outlet pressure. The gas valve is
factory-set for the correct outlet pressure.
This setting is suitable for natural gas
and propane (when configured for LP),
requiring no field adjustment. Attempting
to alter or measure the gas valve outlet
pressure could result in damage to the
valve, causing potential severe personal
injury, death, or substantial property
damage.
operation to avoid flue gas emission from
the condensate drain line. Failure to fill the
trap could result in severe personal injury
or death.
Final checks before starting the water
heater
Read this manual to familiarize yourself with electronic
control module operation. Read pages 49 and 50 for proper
steps to start the water heater.
Figure 9-1 Condensate Trap
Verify the water heater and system are full of water and all
2" PVC CAP WITH
BLOCKED DRAIN SWITCH
system components are correctly set for operation.
Verify the preparation procedures of Section 9, pages 47
CONDENSATE FROM
HEAT EXCHANGER
RETAINING SCREW
and 48 have been completed.
Fill the vent condensate trap with water (removing the
retaining screw in order to remove the 2 inch PVC cap with
the switch located at the top of the trap). Replace the cap.
Press the cap onto the trap until the cap makes contact with
the drain. Replace the retaining screw.
CONDENSATE DRAIN
Verify electrical connections are correct and securely
attached.
Inspect vent piping and air piping for signs of deterioration
from corrosion, physical damage or sagging. Verify air
piping and vent piping are intact and correctly installed per
this manual.
REMOVABLE CAP
TO CLEAN OUT TRAP
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Installation & Service Manual
9 Start-up
Start the water heater
Check flame and combustion
1. Press the SHUTDOWN button on the display until
1. Read and follow the Operating instructions in FIG.’s 9-2 and
9-3, pages 49 and 50.
HTR:Off appears in the display window.
2. Remove the screws securing the top panel to the unit.
Remove the panel from the unit to gain access to the flue
sensor.
If water heater does not start correctly
1. Check for loose connections, blown fuse or service switch
off.
3. Locate the flue sensor in the top of the vent connection.
Remove the flue sensor and grommet from the unit.
Note: Combustion measurements will be made at this
point.
2. Is external limit control (if used) open? Is water temperature
above 200°F?
3. Is tank set point set below tank temperature?
4. Is gas turned on at meter and water heater?
5. Is incoming gas pressure less than 4 inches w.c.?
4. Press the SHUTDOWN button on the display until
HTR:Standby appears in the display window.
5. Locate the pinhole button above the “r” in the Lochinvar
logo on the display board (FIG. 10-1). Insert a thin wire
(such as a paper clip) into the hole and press the button
once and hold for 5 seconds to place the water heater
into Service Mode. In Service Mode the water heater will
fire at ignition speed and will then modulate up to full
fire.
If none of the above corrects the problem, refer to the
Troubleshooting section of this manual.
Check system and water heater
Check water piping
1. Check system piping for leaks. If found, shut down the water
heater and repair immediately. (See WARNINGS on pages
47 and 48 (startup) regarding failure to repair leaks.)
6. Insert the probe from a combustion analyzer into the
hole left by the removal of the flue temperature sensor.
7. Once the water heater has modulated up to full fire,
measure the combustion. The values should be in the
range listed in Table 9A. The CO levels should be less
than 150 ppm for a properly installed unit.
2. Check Delta T. Ensure Delta T is less than 25°F.
3. Vent any remaining air from the system using manual vents.
Air in the system will interfere with circulation and cause
hot water distribution problems and noise.
If the combustion is not within the specified range,
reference the Troubleshooting section of this manual for
possible causes and corrective actions.
Check vent piping and air piping
1. Check for gastight seal at every connection, seam of air
piping, and vent piping.
Table 9A Flue Products Chart
Natural Gas
Propane
Venting system must be sealed gastight
ƽ WARNING
to prevent flue gas spillage and carbon
CO2
8.0% - 10%
O2
CO2
9.0% - 11%
O2
monoxide emissions, which will result in
severe personal injury or death.
3.0% - 6.5%
4.1% - 6.9%
Check gas piping
8. Once the combustion analysis is complete, press the
SHUTDOWN button on the display board (FIG. 10-1)
to take the water heater out of Service Mode. The
water heater will go to shutdown and the display will
show HTR:Off.
1. Check around the water heater for gas odor following
the procedure on page 39 of this manual (Connecting Gas
Supply Piping).
If you discover evidence of any gas leak,
ƽ WARNING
9. Replace the flue sensor and grommet into the vent
connection.
shut down the water heater at once. Find
the leak source with a bubble test and repair
immediately. Do not start the water heater
again until corrected. Failure to comply
could result in severe personal injury, death,
or substantial property damage.
10. Replace the top panel on the unit.
11. Place the Shield water heater back into normal operation.
You must replace the flue sensor to
ƽ WARNING
prevent flue gas spillage into the room.
Failure to comply could result in severe
personal injury, death, or substantial
property damage.
48
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Installation & Service Manual
9 Start-up
(continued)
Figure 9-2 Operating Instructions - Models SNR150-100 -- SNA285-125
49
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Installation & Service Manual
9 Start-up
Figure 9-3 Operating Instructions - Models SNA400-125 -- SNA500-125
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10 Operating information
The control monitors the temperature difference between the
heat exchanger inlet and the heat exchanger outlet sensors. If
this difference exceeds 25°F the control will reduce the fan
speed. If the temperature difference exceeds 30°F the control
will shut the unit down. The unit will restart automatically
once the temperature difference has dropped below 25°F and the
minimum off time has expired.
General
How the water heater operates
The Shield water heater combines an advanced stainless
steel heat exchanger, electronic control module, and tank
that allows fully condensing operation. The blower pulls in
air and pushes flue products out of the heat exchanger and
flue piping. The control module regulates blower speed to
control the water heater firing rate. The gas valve senses
the amount of air flowing into the water heater and allows
only the right amount of gas to flow. An internal pump
circulates the water between the tank and heater and mixes
the incoming water to provide maximum efficiency.
Freeze protection
DO NOT install the water heater in a room likely to freeze.
The following integral feature of the electronic control module
provides some protection for the water heater.
•
The electronic control module provides freeze-
up protection as follows when the water heater water
temperature drops below 45°F:
Below 45°F, the internal pump operates constantly.
Below 37°F, the burner turns on.
Temperature control
Modulation
•
•
•
The Shield water heater is capable of modulating its firing
rate from a minimum of 20% to a maximum of 100%. The
firing rate is dictated by the hot water draw and various other
temperature limitations.
The burner and pump will turn off if water
heater water temperature rises above 45°F.
This feature of the electronic control module
ƽ CAUTION
does not eliminate the possibility of freezing.
The installation must still use recognized
design, installation and maintenance practice
to prevent freeze potential for the water
heater.
Night setback
The controller may be programmed to reduce the tank set
point during a certain time each day. A start and stop time
can be programmed for each day of the week.
Monitor external limits
Flame current support
Connections are provided on the connection board for external
limits. The electronic control module will shut off the burner
and inhibit relighting whenever an external limit opens.
To prevent nuisance shutdowns when the water heater is
firing at minimum rates, the control will increase fan speed
when the flame signal drops too low.
Runtime and alarm outputs
Protection features
The water heater provides dry contacts for indicating when the
water heater is running, and when it is unable to operate.
Outlet temperature, flue temperature, and
temperature rise limiting
Error logging
The heat exchanger outlet temperature is monitored by the
heat exchanger outlet temperature sensor. When the heat
exchanger outlet temperature exceeds 190°F, the unit will
reduce the fan speed. If the heat exchanger outlet water
temperature exceeds 198°F the control will shut the unit
down until it cools off.
The control will hold in memory the last 10 faults. The date
and time of the occurrence will be recorded as well. Only the 10
most current occurrences will be held in memory.
The control module monitors the flue temperature by a
sensor located in the flue exhaust. If the flue temperature
exceeds 215°F the control will reduce the maximum fan
speed. If the flue temperature exceeds 240°F the control will
shut the unit down. The unit will restart automatically once
the flue temperature drops 25°F and the minimum off time
has expired.
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Installation & Service Manual
10 Operating information
Water heater temperature regulation
Operating temperature (target)
Tank Differential
Once the tank set point is satisfied, the tank temperature must
drop below the set point by this amount before the heater will
fire again. The temperature range of this parameter is 3.6°F to
18°F. The default value is 6.3°F.
The electronic control module senses water temperature in
the tank and regulates water heater ignition and firing rate to
achieve a target temperature. The target temperature can be
set between 60°F and 185°F.
Temperature units (°F/°C)
High limit operations
The control can be configured to display temperature in either
°C or °F. This setting can be changed by the user or the installer.
The default is °F.
When the heat exchanger outlet temperature exceeds 203°F,
high limit action occurs. The burner shuts down until the
heat exchanger outlet water cools down, and requires manual
reset of the control before operation will resume. To reset
control, push the RESET key on the display.
Night setback temperature
Once the internal clock has been set correctly, the night setback
feature can be used to program a lower tank set point. The
temperature range for this parameter is 32°F to 140°F. The
feature is turned off with a setting of 32°F. The default value
is 32°F.
Low water cutoff protection
1. The electronic control module uses sensing of both
heat exchanger supply and return temperatures. If the
flow rate is too low or either temperature too high, the
control module modulates and shuts the burner down.
This ensures water heater shutdown in the event of low
water or low flow conditions in the heat exchanger.
Night setback times
If the night setback temperature is set to anything other than
32°F, the night setback feature becomes active. This will
require start and stop times to be programmed for the days
that reduced temperatures are required. Each day of the week
(Sunday through Saturday) will have an ON and OFF time.
Adjustable control parameters
To access the control parameters, press the MENU button on
the display. When finished, press the MENU button again to
return to the status display. Use the NEXT and PREVIOUS
buttons to select the parameter you wish to change.
Night setback can be programmed to skip certain days of the
week, and to remain active throughout certain days of the
week. To skip a day, set the ON and OFF times for that day to
any time before 12:00 (noon), and equal to each other. Night
setback will become inactive at the OFF time on the previous
day, and remain inactive until the ON time on the following
day. To have night setback remain active throughout an entire
day, set the ON and OFF times to any time after 12:00 (noon),
and equal to each other. Night setback will become active at the
ON time on the previous day, and remain active until the OFF
time on the following day.
Date and time
The control uses an internal clock for the night setback
feature and for logging of events. For these features to work
correctly, the clock must be set when the water heater is first
installed or anytime the water heater has been powered off
for more than 30 days. The date and time are displayed as
“MM:DD:YY W hh:mm”. MM = month, DD = date, YY =
year, W = day (1 = Monday, 2 = Tuesday, etc.), hh = hour
(24 hour time; 2:00 PM = 14:00), mm = minutes.
Saving parameters
To save parameters:
The internal clock does not adjust for
Daylight Savings Time and therefore, will
require a manual adjustment.
NOTICE
Press the ENTER/RESET button.
To keep parameter settings only for a current operating cycle:
Tank set point
Press the MENU/EXIT button 1 time to return to the status
display.
When a HW call for heat becomes active, the control will
use the tank set point to determine the firing rate of the
water heater based on the actual water temperature. The
temperature range of this parameter is 60°F to 185°F. The
default value is 125°F.
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10 Operating information
(continued)
Sequence of operation
OPERATION
DISPLAY
HTR: Standby
TANK: 123.8F(129)
1. When the tank temperature falls below the set point minus the
differential, the control will start the burner.
2. The control connects 120 VAC to the blower. The blower does
not run at this time.
HTR: Standby
TANK: 123.8F(129)
• The manual reset high limit must be closed before the control
powers up the blower.
• The control starts the internal pump.
• If there is an external limit connected to the heater, it must be
closed.
HTR: PREPURGE
TANK: 123.9F(129)
3. The control then starts the prepurge cycle.
4. Once the prepurge cycle is complete, and the blocked drain
switch and auto-reset high limit are closed, the control starts the
trial for ignition by sending spark voltage to the spark electrode
and opening the gas valve.
HTR: IGNITION
TANK: 123.9F(129)
5. If the control does not detect flame by the end of the trial for
ignition, the control performs the postpurge, another prepurge
and tries to light the burner again. If the burner does not light
after 4 trials, the control locks out for 1 hour and then tries another
set of 4 trials.
HTR: POSTPURGE, PREPURGE
TANK: 123.9F(129)
HTR: RUN 20% RATE
TANK: 124.8F(129)
6. If the control detects a flame before the trial for ignition ends, it
begins to modulate the burner in order to maintain the set point.
7. Once the tank temperature goes 3 - 4°F above the set point, the
control will turn off the burner. The blower will remain on for the
postpurge cycle. The internal pump will continue to run for its
pump delay time, then turn off.
HTR: POSTPURGE
TANK: 127.4F(129)
HTR: Standby
TANK: 124.7F(129)
8. Burner off.
53
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Installation & Service Manual
10 Operating information
Shield control module
Use the control panel (FIG. 10-1) to set temperatures, operating conditions, and monitor water heater operation.
Figure 10-1 Control Panel
• Press once to go into Menu Mode
• Press again to exit Menu Mode
• Press to toggle between digits when
entering the hour, minutes, etc., or
when entering date and time
54
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Installation & Service Manual
10 Operating information
(continued)
Status display screens
Status Display Screens
By using the Previous/Next (, ) arrow keys on the electronic control module display panel, you can navigate through the
five (5) display screens. Each screen will contain two (2) viewable items. The following is a description of the individual items
and what they can display:
Screen
Display shows:
Description
The unit has been turned OFF by the Enter/Reset button on the
electronic control module display panel.
HTR: OFF
Standby
The unit has not received a call for heat.
Prepurge
Ignition
The unit has initiated a prepurge period on a call for heat.
The unit has begun a spark period to ignite the main burner.
The unit has fired and is running at the displayed percentage.
RUN***% Rate
#1
The call for heat has been satisfied and the unit runs the fan for an
additional postpurge period to clear the combustion chamber and vent
system of residual flue products.
Postpurge
The unit has been placed in a temporary mode that will allow the unit to
fire at 100% of rate for the purpose of combustion analysis.
Service
TANK:***.*F
The tank temperature is displayed.
Open
The control does not detect the tank sensor.
Shorted
The tank sensor wires or the sensor itself has become shorted.
Press the Next arrow key on the electronic control module display to access Screen #2.
HEX IN: ***.*F
Open
The temperature at the inlet to the heat exchanger is displayed.
The control does not detect the heat exchanger inlet sensor.
The heat exchanger inlet sensor wires or the sensor itself has become
shorted.
Shorted
#2
HEX OUT: ***.*F
Open
The temperature at the outlet of the heat exchanger is displayed.
The control does not detect the heat exchanger outlet sensor.
The heat exchanger outlet sensor wires or the sensor itself has become
shorted.
Shorted
Press the Next arrow key on the electronic control module display to access Screen #3.
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Installation & Service Manual
10 Operating information
Status Display Screens (cont’d)
By using the Previous/Next (, ) arrow keys on the electronic control module display panel, you can navigate through the
five (5) display screens. Each screen will contain two (2) viewable items. The following is a description of the individual items
and what they can display:
Screen
Display shows:
Description
The control will display the temperature difference between the
outlet and inlet of the heat exchanger.
RISE: ***.*F
FLUE: ***.*F
Open
The control will display the flue temperature.
#3
The control does not detect the flue sensor.
Shorted
The flue sensor wires or the sensor itself has become shorted.
Press the Next arrow key on the electronic control module display to access Screen #4.
FAN SPD: ****RPM
FLAME SIG: **.*uA
The control will display the actual fan motor RPM.
#4
#5
The control will display the flame signal in dc microamps.
Press the Next arrow key on the electronic control module display to access Screen #5.
FAULT 01 MM:DD:YY
(fault)
This screen allows the user to view the last 10 faults. The most recent
fault is shown first. The top line of the display shows the fault number,
and alternates between the date of the fault (MM:DD:YY) and the time
(hh:mm). The bottom line shows cause of the fault. To view earlier
faults, press the UP key. To review later faults, press the DOWN key.
FAULT 01 hh:mm
(fault)
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Installation & Service Manual
11 Maintenance
Maintenance and annual startup
Table 11A Service and Maintenance Schedules
Service technician
Owner maintenance
(see the following pages for instructions)
General:
• Address reported problems
• Inspect interior; clean and vacuum if
necessary;
• Clean condensate trap and fill with fresh
water
• Check water heater area
Daily
• Check for leaks (water, gas, flue,
condensate)
• Verify flue and air lines in good condition
and sealed tight
• Check system water pressure/system
piping/expansion tank
• Check control settings
• Check ignition and flame sense electrodes
(sand off any deposits; clean and
reposition)
• Check vent piping
• Check wiring and connections
• Check air piping
• Perform
start-up
checkout
and
• Check relief valve
performance verification per Section 9
in this manual.
Monthly
• Check condensate drain system
• Check Delta T (Temperature Rise)
• Flame inspection (stable, uniform)
• Flame signal (at least 10 microamps at
high fire)
• Clean the heat exchanger if flue
temperature is more than 54°F above
return water temperature.
• Check anode rods.
• Check Delta T (Temperature Rise)
If combustion or performance
indicate need:
Every
6 months
•Check water heater piping
(gas and water) for leaks
• Clean heat exchanger
• Operate relief valve
• Remove and clean burner using
compressed air only
• Clean the blower wheel
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Installation & Service Manual
11 Maintenance
Follow the service and maintenance procedures given throughout this manual and in component literature
shipped with the water heater. Failure to perform the service and maintenance could result in damage to the
water heater or system. Failure to follow the directions in this manual and component literature could result
in severe personal injury, death, or substantial property damage.
ƽ WARNING
The water heater should be inspected annually only by a qualified service technician. In addition, the
maintenance and care of the water heater designated in Table 11A and explained on the following pages must
be performed to assure maximum water heater efficiency and reliability. Failure to service and maintain the
water heater and system could result in equipment failure.
ƽ WARNING
Electrical shock hazard – Turn off power to the water heater before any service operation on the water heater
except as noted otherwise in this instruction manual. Failure to turn off electrical power could result in
electrical shock, causing severe personal injury or death.
ƽ WARNING
The condensate trap must be filled with water
Address reported problems
ƽ WARNING
during all times of water heater operation to
avoid flue gas emission from the condensate
drain line. Failure to fill the trap could result
in severe personal injury or death.
1. Inspect any problems reported by the owner and correct
before proceeding.
Inspect water heater area
1. Verify that water heater area is free of any combustible
materials, gasoline and other flammable vapors and
liquids.
Check all piping for leaks
Eliminate all system or water heater leaks.
ƽ WARNING
Leaking water may cause severe property
damage.
2. Verify that air intake area is free of any of the contaminants
listed in Section 1 of this manual. If any of these are
present in the water heater intake air vicinity, they must
be removed. If they cannot be removed, reinstall the air
and vent lines per this manual.
1. Inspect all water and gas piping and verify to be leak free.
2. Look for signs of leaking lines and correct any problems
found.
3. Check gas line using the procedure found in Section 7 - Gas
Connections.
Inspect water heater interior
1. Remove the front access cover and inspect the interior of
Flue vent system and air piping
the water heater.
1. Visually inspect the entire flue gas venting system and air
piping for blockage, deterioration or leakage. Repair any
joints that show signs of leakage. Verify that air inlet pipe is
connected and properly sealed.
Clean condensate trap
1. Remove the clean out cap on the bottom of the trap. Let
the condensate and any debris drain out.
2. Verify that water heater vent discharge and air intake are
clean and free of obstructions.
2. Replace the clean out cap.
3. Fill with fresh water until the water begins to pour out of
the drain.
Failure to inspect for the above conditions
and have them repaired can result in severe
personal injury or death.
ƽ WARNING
4. Resume operation.
Figure 11-1 Condensate Trap
Check water system
2" PVC CAP WITH
BLOCKED DRAIN SWITCH
1. Verify all system components are correctly installed and
operational.
CONDENSATE FROM
HEAT EXCHANGER
RETAINING SCREW
CONDENSATE DRAIN
2. Check the cold fill pressure for the system. Verify it is
correct (must be a minimum of 12 PSI).
3. Watch the system pressure as the water heater heats up
(during testing) to ensure pressure does not rise too high.
Excessive pressure rise indicates expansion tank sizing or
performance problem.
4. Inspect automatic air vents and air separators. Remove air
vent caps and briefly push valve to flush vent. Replace caps.
Make sure vents do not leak. Replace any leaking vents.
REMOVABLE CAP
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Installation & Service Manual
11 Maintenance
(continued)
2. After following the warning directions, if the relief valve
weeps or will not seat properly, replace the relief valve.
Ensure that the reason for relief valve weeping is the valve
and not over-pressurization of the system due to expansion
tank waterlogging or undersizing.
Check expansion tank
1. Expansion tanks provide space for water to move in and
out as the water expands due to temperature increase or
contracts as the water cools. Tanks must be approved for
potable water systems. See Section 5 - System Piping for
suggested best location of expansion tanks.
Inspect ignition and flame sense
electrodes
Check water heater relief valve
1. Remove the ignition and flame sense electrodes from the
1. Inspect the relief valve and lift the lever to verify flow.
Before operating any relief valve, ensure that it is
piped with its discharge in a safe area to avoid severe
scald potential. Read Section 5 - System Piping before
proceeding further.
water heater heat exchanger access cover.
2. Remove any deposits accumulated on the ignition/flame
sense electrode using sandpaper. If the electrodes cannot be
cleaned satisfactorily, replace with new ones.
Safety relief valves should be re-inspected
ƽ WARNING
3. Replace ignition/flame sense electrode, making sure gasket
is in good condition and correctly positioned.
AT LEAST ONCE EVERY THREE
YEARS, by a licensed plumbing contractor
or authorized inspection agency, to
ensure that the product has not been
affected by corrosive water conditions
and to ensure that the valve and discharge
line have not been altered or tampered
with illegally. Certain naturally occurring
conditions may corrode the valve or its
components over time, rendering the
valve inoperative. Such conditions are
not detectable unless the valve and its
components are physically removed and
inspected. This inspection must only be
conducted by a plumbing contractor or
authorized inspection agency – not by
the owner. Failure to re-inspect the water
heater relief valve as directed could result
in unsafe pressure buildup, which can
result in severe personal injury, death, or
substantial property damage.
Check ignition ground wiring
1. Inspect water heater ground wire from the heat exchanger
access cover to ground terminal strip.
2. Verify all wiring is in good condition and securely attached.
3. Check ground continuity of wiring using continuity meter.
4. Replace ground wires if ground continuity is not satisfactory.
Check all water heater wiring
1. Inspect all water heater wiring, making sure wires are in
good condition and securely attached.
Check control settings
1. Set the control module display to Parameter Mode and
check all settings. Adjust settings if necessary. See Section
1 of this manual for adjustment procedures.
Following installation, the valve lever
must be operated AT LEAST ONCE
2. Check settings of external limit controls (if any) and adjust
if necessary.
ƽ WARNING
A YEAR to ensure that waterways are
clear. Certain naturally occurring
mineral deposits may adhere to the valve,
rendering it inoperative. When manually
operating the lever, water will discharge
and precautions must be taken to avoid
contact with hot water and to avoid water
damage. Before operating lever, check
to see that a discharge line is connected
to this valve directing the flow of hot
water from the valve to a proper place of
disposal. Otherwise severe personal injury
may result. If no water flows, valve is
inoperative. Shut down the water heater
until a new relief valve has been installed.
Perform start-up and checks
1. Start water heater and perform checks and tests specified in
Section 9 - Start-up.
2. Verify cold fill pressure is correct and that operating
pressure does not go too high.
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11 Maintenance
Check burner flame
Handling ceramic fiber materials
1. Inspect flame through observation window.
REMOVAL OF COMBUSTION CHAMBER
LINING
2. If the flame is unsatisfactory at either high fire or low
fire, turn off water heater and allow water heater to
cool down. Remove the burner and clean it thoroughly
using a vacuum cleaner or compressed air. Do not use
compressed air to clean burner if performed inside a
building.
The combustion chamber insulation in
ƽ WARNING
this appliance contains ceramic fiber
material. Ceramic fibers can be converted
to cristobalite in very high temperature applications. The
International Agency for Research on Cancer (IARC) has
concluded, “Crystalline silica inhaled in the form of quartz
or cristobalite from occupational sources is carcinogenic to
humans (Group 1).” Normal operating temperatures in this
appliance are below the level to convert ceramic fibers to
cristobalite. Abnormal operating conditions would have to
be created to convert the ceramic fibers in this appliance to
cristobalite.
3. Remove the burner, reference FIG. 11-2 below.
4. When replacing the burner, ensure gasket is in good
condition and positioned correctly (FIG. 11-2).
Figure 11-2 Burner Assembly
The ceramic fiber material used in this appliance is an irritant;
when handling or replacing the ceramic materials it is advisable
that the installer follow these safety guidelines.
Avoid breathing dust and contact with skin and eyes.
• Use NIOSH certified dust respirator (N95). This type of
respirator is based on the OSHA requirements for cristobalite
at the time this document was written. Other types of
respirators may be needed depending on the job site
conditions. Current NIOSH recommendations can be found
NIOSH approved respirators, manufacturers, and phone
numbers are also listed on this website.
• Wear long-sleeved, loose fitting clothing, gloves, and eye
protection.
Check flame signal
1. At high fire the flame signal shown on the display should
Apply enough water to the combustion chamber lining to
prevent airborne dust.
be at least 10 microamps.
Remove the combustion chamber lining from the appliance
and place it in a plastic bag for disposal.
2. A lower flame signal may indicate a fouled or damaged
flame sense electrode. If cleaning the flame sense electrode
does not improve, ground wiring is in good condition,
and ground continuity is satisfactory, replace the flame
sense electrode.
Wash potentially contaminated clothes separately from
other clothing. Rinse clothes washer thoroughly.
NIOSH stated First Aid.
Eye: Irrigate immediately.
Breathing: Fresh air.
3. See Section 12 - Troubleshooting for other procedures to
deal with low flame signal.
Cleaning heat exchanger
For recommended materials; including brush, appropriate
extension(s), refractory cover, and detailed instructions see
Table 11B - Heat Exchanger Cleaning Kits on page 61.
Review with owner
1. Emphasize the need to perform the maintenance schedule
specified in this manual.
2. Remind the owner of the need to call a licensed contractor
should the water heater or system exhibit any unusual
behavior.
1. Shut down water heater:
• Follow the “To Turn Off Gas to Appliance” instructions
for the water heater in Section 9 - Startup.
• Do not drain the water heater unless it will be exposed
to freezing temperatures. If using freeze prevention
fluid in system, do not drain.
2. Allow time for the water heater to cool to room temperature
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Installation & Service Manual
11 Maintenance
(continued)
3. Remove the nuts securing the heat exchanger access cover
to the heat exchanger and set aside.
Figure 11-3 Rope Gasket - Heat Exchanger Door
4. Remove the heat exchanger access cover, burner, and
gas/air arm assembly.
ROPE GASKET
The water heater contains ceramic fiber
ƽ WARNING
materials. Use care when handling these
materials per instructions in this manual.
Failure to comply could result in severe
personal injury.
CAUTION: IF GASKET IS DAMAGED
DO NOT REUSE, THE HEAT EXCHANGER DOOR
MUST BE REPLACED.
5. Remove the condensate hose from the heat exchanger
end. Connect a field supplied 3/4" diameter hose to
a drain pan. Using field supplied means, cover the
refractory in the back of the combustion chamber of the
heat exchanger.
Rope gasket is intended for sealing combustion
(FIG. 11-3). If damaged DO NOT reuse, the
heat exchanger door must be replaced. Consult
factory for replacement heat exchanger door
(kit WTR3080).
NOTICE
6. Use a vacuum cleaner to remove any accumulation on
the water heater heating surfaces. Do not use any solvent.
7. Brush the heat exchanger while dry using a nylon
bristle brush. Caution: DO NOT use a metal brush.
Re-vacuum the heat exchanger.
Oiled bearing circulators
1. The circulator shipped with the Shield water heater is water-
lubricated. No oiling is required.
8. Finish cleaning using a clean cloth dampened with warm
water. Rinse out debris with a low pressure water supply.
2. Check other circulators in the system. Oil any circulators
requiring oil, following circulator manufacturer’s
instructions. Over-oiling will damage the circulator.
9. Allow the heat exchanger to thoroughly dry.
10. Remove the field supplied rear refractory cover from the
back of the combustion chamber of the heat exchanger
and reassemble.
Magnesium anode rod inspection
Glass lined storage tanks have a magnesium anode(s) (FIG. 11-4)
to provide cathodical protection of the lining and minimize
corrosion. Aggressive water conditions in some areas of the
country may accelerate the deterioration of the anode(s). The
anode(s) should be periodically removed and inspected to
determine if replacement is necessary.
11. Close isolation valves on piping to isolate water heater
from system. Attach a hose to the water heater drain and
flush water heater thoroughly with clean water by using
purging valves to allow water to flow through the water
make-up line to the water heater.
The heater must be valved off from the system and fully drained
to remove an anode for inspection. Anodes are supplied in
threaded fittings on the side of the tank. Adequate service
clearance is required to allow removal of an anode. The anode(s)
should be replaced when more than six inches of the core wire is
exposed at either end of the rod.
12. Perform start-up and check-out procedures in the Check
Flame and Combustion - Section 9 - Startup on page 48
of this manual.
13. Replace the access cover and restore water heater to
operation.
Table 11B Heat Exchanger Cleaning Kits
Figure 11-4 Anode Location
Kit
Part
Component
Description
Model
Number Number
CTN20005
Rear Refractory Cover
Nylon 4" Wheel Brush*
3mm Allen Wrench
ANODE RODS
SNR150-100
SNR200-100
SNA285-125
SNA400-125
MSC20083*
KIT30063
MSC20084
MSC20086 1/4" x 24" Drill Extension
CTN20005
Rear Refractory Cover
Nylon 4" Wheel Brush*
MSC20083*
Anode rods showing excessive decomposition
NOTICE
SNA500-125 KIT30064
MSC20085 1/4" x 12" Drill Extension
MSC20086 1/4" x 24" Drill Extension
may indicate electrolysis. An earth ground
should be attached to the vessel to divert
stray current and prevent tank damage.
* Do NOT use a metal brush. Only use
the kit provided brush or an equivalent
ƽ CAUTION
Check Delta T
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Ensure Delta T is less than 25°F.
replacement nylon brush.
61
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Installation & Service Manual
12 Troubleshooting
Check control module fuses
Label all wires prior to disconnection
ƽ WARNING
when servicing controls. Wiring errors
can cause improper and dangerous
operation. Always disconnect power
to the water heater before servicing.
Failure to comply could result in severe
personal injury, death, or substantial
property damage.
ALWAYS check control module fuses
NOTICE
before replacing control module or any
major components (blower, etc.). If one
of these fuses is blown, it can prevent the
control module or other components from
operating.
1. Turn OFF power to the water heater at the external
disconnect switch.
Never jumper (bypass) any device except
for momentary testing as outlined in the
Troubleshooting chart. Severe personal
injury, death, or substantial property
damage can result.
ƽ WARNING
2. Remove top access cover.
3. Remove the control module cover.
4. Inspect fuses F2, F3, F4, and F5, see FIG. 12-1 below.
Before troubleshooting:
Figure 12-1 Control Module Fuses
1. Have the following items:
a. Voltmeter that can check 120 VAC, 24 VAC, and
12 VDC.
F3 - 1.25 AMP FUSE
MAIN BOARD
b. Continuity checker.
c. Contact thermometer.
F4 - 3.15 AMP FUSE
BLOWER
2. Check for 120 VAC (minimum 102 VAC to maximum
132 VAC) to water heater.
F5 - 5 AMP FUSE
PUMPS
3. Make sure the tank is calling for heat.
F2 - 3.15 AMP FUSE
24V SUPPLY
4. Make sure all external limit controls are installed and
operating.
Check the following:
1. Wire connectors to control module and connection
board are securely plugged in.
5. The water heater is shipped with three (3) spare fuses in a
plastic bag attached to the control module cover.
2. Gas pressures:
6. If necessary, replace open fuse (F3 is 1.25 amps, F2 and F4
are 3.15 amps, and F5 is 5 amps).
• Maximum: 14 inches w.c. (natural and LP) with no
flow (lockup) or with water heater on
• Minimum: 4 inches w.c. (natural), 8 inches w.c. (LP)
with gas flowing (verify during water heater startup)
Note: Fuses F2 - F5 are all slow blow fuses.
Do not jumper fuse or replace with any fuse
ƽ WARNING
except as specified. Failure to comply could
result in severe personal injury, death, or
substantial property damage.
7. Install control module cover and top access cover after fuse
inspection.
8. Restore power to the water heater at the external
disconnect switch and verify water heater operation
(Section 9 - Start-up) after completing water heater service.
62
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12 Troubleshooting
(continued)
Table 12A Troubleshooting Chart - No Display
FAULT
CAUSE
CORRECTIVE ACTION
- No 120 VAC supplied to unit.
• Check external line switch, fuse, or breaker.
• Check wiring harness connection between display
board and main control board. Connect harness at both
points.
No Display
- Bad display board.
• Replace board.
- Bad main control board.
- Blown fuse.
• Replace the main control board.
• Replace fuse F3 on the main control board, see
page 62 of this manual.
- Tank temperature set point satisfied.
- Unit locked out on fault.
• Review temperature setting.
No Burner
Operation
• Consult display for specific fault. Refer to fault
descriptions on page 66 of this manual for corrective
actions.
- Flue sensor open.
• Verify that the flue sensor is located in the flue outlet.
• Check wiring connections at the flue sensor.
Unit Does
Not Modulate
Above 50%
• Check the resistance of the flue sensor and compare
to Table 12C on page 64 of this manual.
63
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12 Troubleshooting
Checking temperature sensors
The water heater temperature sensors (inlet water, outlet water, tank water, and flue) are all resistance type devices. The following
tables show the correct values for the sensors at various temperatures. Use an ohmmeter to read the resistance of the sensor at a
known temperature. If the resistance of the sensor does not closely match its corresponding table, replace the sensor.
Table 12B - Inlet/Outlet Tank Sensor Resistance vs. Temperature
Temperature °F
Resistance
Temperature °F
Resistance
50
68
18,780
12,263
8,194
5,592
3,893
2,760
158
176
194
212
--
1,990
1,458
1,084
817
--
86
104
122
140
--
--
Table 12C - Flue Temperature Sensor Resistance vs. Temperature
Temperature °F
Resistance
Temperature °F
Resistance
68
14,773
9,804
6,652
4,607
3,252
2,337
176
194
212
230
248
--
1,707
1,266
952
726
560
--
86
104
122
140
158
64
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12 Troubleshooting
(continued)
Table 12D Troubleshooting Chart - Noisy System
FAULT
CAUSE
CORRECTIVE ACTION
- Supply gas problem. Natural gas pressures
should be between 4 inches w.c. and • Refer to Section 6 - Gas Connections for detailed
14 inches w.c. LP gas pressures should information concerning the gas supply.
be between 8 inches w.c. and 14 inches w.c.
• Refer to the Gas Valve Adjustment Procedure on
page 73 of this manual for the proper gas valve setting.
Verify that the vent/air intake lengths do not exceed the
- Gas/air mixture problem.
Noisy
Operation
maximum listed in the General Venting section.
• Refer to page 60 in this manual for the burner removal
- Dirty/damaged burner.
and inspection procedure. Clean or replace the burner
as necessary.
• Refer to Section 5 - System Piping for minimum flow
rates.
- Low water flow through the heat exchanger.
- Air in the piping system.
- Blown fuse.
• Properly purge all air from the piping system.
• Replace fuse F5 on the control board, see page 62 of
this manual.
- Faulty pump.
• Replace pump.
No Pump
Operation
- Faulty pump relay.
- Internal fault on control board.
• Replace pump relay.
• Replace main control board.
Relief Valve
Opening
- System pressure exceeds relief valve • Lower the system pressure below the 150 PSI rating of
setting. the supplied relief valve.
65
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12 Troubleshooting
Table 12E Troubleshooting Chart - Fault Messages Displayed on Water Heater Interface
FAULT
DESCRIPTION
CORRECTIVE ACTION
• Check supply voltage for proper polarity.
• Check external wiring for voltage feedback.
• Check the flame rod and make sure it is clean.
• Check the internal wiring for bad connections.
• Replace main control board.
Flame
Sequence
(will require a manual
reset once the condition
has been corrected.
Press the RESET button
on the display to reset.)
The flame detector circuit is seeing a flame
signal while no flame is present.
• Ensure gas valve switch is ON (Models SNR150-100
and SNA285-125).
• Check wiring harness connection at the gas valve and
at the main control board.
• Inspect spark electrode and associated wiring for
damage and connection. Reference page 60 of this
manual for removal and cleaning procedures.
Replace if necessary.
• Check for proper electrical grounding of the unit.
• Check incoming supply gas pressure. Natural gas
pressures should be between 4 - 14 inches w.c. and
LP gas pressures should be between 8 - 14
inches w.c. Refer to Section 6 - Gas Connections for
detailed information concerning the gas supply.
• Verify that the plastic hose from the gas valve to the
air inlet is connected and is not damaged.
• Verify that the vent/air intake pipes are correctly
installed and that there are no obstructions.
No Flame Ign
(will require a manual
reset once the condition
has been corrected.
Press the RESET button
on the display to reset.)
The unit has failed to prove main burner
ignition after four (4) attempts.
• Check for 24 VAC to the gas valve at the 2-pin
connection on the side of the main control board
during the ignition attempt. If no voltage is present,
replace the main control board.
• If 24 VAC is present at the main control board, check
the wiring between the main control board and the
gas valve. Replace the wiring if necessary.
• If 24 VAC is present, check the outlet of the valve to
ensure the valve is flowing gas. With a manometer
connected to the outlet tap of the gas valve, when the
unit is in the prepurge period, there should be a
negative pressure present. When the valve is
energized a change in pressure should occur. If the
pressure change does not occur, the gas valve is not
opening. Replace the gas valve.
• Inspect flame sensor and associated wiring.
Reference page 60 of this manual for removal and
cleaning procedures. Replace if necessary.
• Inspect the burner. Reference page 60 of this manual
for removal and cleaning procedures. Replace if
necessary.
• Replace the main control board.
66
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12 Troubleshooting
(continued)
Table 12E (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater
Interface
FAULT
DESCRIPTION
CORRECTIVE ACTION
• Ensure gas valve switch is ON (Models SNR150-100
and SNA285-125).
• Check wiring harness connection at the gas valve and
at the main control board.
• Inspect spark electrode and associated wiring for
damage and connection. Reference page 60 of this
manual for removal and cleaning procedures.
Replace if necessary.
• Check for proper electrical grounding of unit.
• Check incoming supply gas pressure. Natural gas
pressures should be between 4 - 14 inches w.c. and
LP gas pressures should be between 8 - 14
inches w.c. Refer to Section 6 - Gas Connections for
detailed information concerning the gas supply.
• Verify that the plastic hose from the gas valve to the air
inlet is connected and is not damaged.
• Verify that the vent/air intake pipes are installed
correctly and there are no obstructions.
No Flame
Running
The unit was running and lost the flame
signal. This condition occurred four (4)
straight times.
(will require a
• Check for 24 VAC to the gas valve at the 2-pin
connection on the side of the main control board
during the ignition attempt. If no voltage is present,
replace the main control board.
manual reset once the
condition has been
corrected. Press the
RESET button on the
display to reset.)
• If 24 VAC is present at the main control board, check
the wiring between the main control board and the gas
valve. Replace the wiring if necessary.
• If 24 VAC is present, check the outlet of the valve to
ensure the valve is flowing gas. With a manometer
connected to the outlet tap of the gas valve, when the
unit is in the prepurge period, there should be a
negative pressure present. When the valve is
energized a change in pressure should occur. If the
pressure change does not occur, the gas valve is not
opening. Replace the gas valve.
• Inspect flame sensor and associated wiring.
Reference page 60 of this manual for removal and
cleaning procedures. Replace if necessary.
• Inspect the burner. Reference page 60 of this manual
for removal and cleaning procedures. Replace if
necessary.
• Replace the main control board.
67
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12 Troubleshooting
Table 12E (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater
Interface
FAULT
DESCRIPTION
CORRECTIVE ACTION
• Verify that the system is full of water and that all air
has been properly purged from the system.
• Verify that the water heater is piped properly into the
heating system. Refer to Section 5 - System Piping
for the proper piping methods for the Shield water
heater.
Manual Reset
High Limit
• Check 120 VAC to water heater pump motor on a call
for heat. If voltage is not present, check wiring back
to the main control board.
The outlet water temperature has exceeded
the fixed setting of the manual reset high
limit.
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
• Replace the main control board if necessary.
• If 120 VAC is present on a call for heat and the water
heater pump is not operating, replace the pump.
• Check resistance of water sensors and compare to
Table 12B on page 64 of this manual. Replace
sensor if necessary.
• Vent/air intake lengths exceed the maximum allowed
lengths. Refer to Section 2 - General Venting for
proper lengths.
Fan Low
OR
Fan Speed Low
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
The actual fan RPM is 30% lower than what
is being called for.
• Check for obstruction or blockage in the vent/air
intake pipes or at terminations.
• Check the wiring connections at the fan and at the
main control board.
• Replace the fan.
• Replace the main control board.
• Replace fuse F4 on the control board, see page 62
of this manual.
Blown fuse.
• Check the wiring connections to switch. Wires
should be connected to the common and normally
closed terminals.
• Air intake lengths exceed the maximum allowed
lengths. Refer to Section 2 - General Venting for
proper lengths.
APS
• Check for obstruction or blockage in the air
intake pipes or at terminations.
Open
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
Air pressure switch contacts are open.
• Check reference hoses connected to the air pressure
switch for blockage or obstruction.
• Inspect the burner. Reference page 60 of this
manual for removal and cleaning procedures.
Replace if necessary.
• Inspect the heat exchanger. Reference page 61 of
this manual for removal and cleaning procedures.
Replace if necessary.
• Faulty air pressure switch. Replace switch.
68
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12 Troubleshooting
(continued)
Table 12E (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater
Interface
FAULT
DESCRIPTION
CORRECTIVE ACTION
• Vent/air intake lengths exceed the maximum allowed
lengths. Refer to Section 2 - General Venting for
proper lengths.
Fan High
OR
Fan Speed High
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
• Check for obstruction or blockage in the vent/air
intake pipes or at terminations.
The actual fan RPM is 30% higher than
what is being called for.
• Check the wiring connections at the fan and at the
main control board.
• Replace the fan.
• Replace the main control board.
• Check the sensors and their associated wiring.
Repair or replace the sensor or wiring if damaged.
Sensor Open
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
Either the heat exchanger inlet water, heat
exchanger outlet water or tank temperature
sensor has been disconnected.
• Measure the resistance of the sensors and compare
the resistance to the tables on page 64 of this
manual.
S1 = Outlet Sensor
S2 = Inlet Sensor
• Replace the sensor if necessary.
• Check the sensors and their associated wiring.
Repair or replace the sensor or wiring if damaged.
Sensor Shorted
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
Either the heat exchanger inlet water heat
exchanger outlet water or tank temperature
sensor has been shorted.
• Measure the resistance of the sensors and compare
the resistance to the tables on page 64 of this
manual.
S1 = Outlet Sensor
S2 = Inlet Sensor
• Replace the sensor if necessary.
External Limit
Switch
• Check function of remote devices.
(will retry after 5
minutes. RESET may be
pressed after condition is
corrected.)
An optional remote limit switch is not making.
• Check for loose or misplaced jumper if external
limit switch is not installed.
Automatic Reset High Limit:
• Verify that the system is full of water and that all air
has been properly purged from the system.
• Verify that the water heater is piped properly into the
heating system. Refer to Section 5 - System Piping
for the proper piping methods for the Shield water
heater.
Automatic Reset
High Limit / HEX
Temp Sw
• Check 120 VAC to water heater pump motor on a call
for heat. If voltage is not present, check wiring back
to the main control board.
Either the automatic reset high limit
(optional), or the O-Temp heat exchanger
switch has opened.
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
• Replace the main control board if necessary.
• If 120 VAC is present on a call for heat and the water
heater pump is not operating, replace the pump.
• Check resistance of water sensors and compare to
Table 12B on page 64 of this manual. Replace
sensor if necessary.
O-TEMP HEX SWITCH
(Applies to the 285-125 --500-125 Models Only):
• Check continuity across two contacts. Wires should
be connected at both poles of the normally closed
switch.
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12 Troubleshooting
Table 12E (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater
Interface
FAULT
DESCRIPTION
CORRECTIVE ACTION
Automatic Reset
High Limit / HEX
Temp Sw
O-TEMP HEX SWITCH
(Applies to the 285-125 --500-125 Models Only):
• Inspect the back of the inner combustion chamber
at burner level for refractory breakdown / missing.
Replace refractory if no damage to the heat
exchanger as a result of the burner, otherwise,
replace the heat exchanger.
Either the automatic reset high limit
(optional), or the O-Temp heat exchanger
switch has opened.
(cont’d)
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
• Faulty O-Temp HEX Switch. Replace switch.
• Inspect the heat exchanger. Reference page 61 of
this manual for the procedure on how to clean the
flue side of the heat exchanger.
• Inspect the flue sensor and associated wiring.
Measure the resistance of the flue sensor and
compare to Table 12C on page 64 of this manual.
Replace the sensor if necessary.
The flue temperature has exceeded the set
parameters for the water heater.
• Verify that the vent/air intake pipes are properly
installed and that there are no obstructions.
• Replace the main control board.
• Deliming may be required.
Scaling has reduced water flow.
• Verify that the system is full of water and that all air
has been properly purged from the system.
The temperature rise across the heat
exchanger has exceeded the set parameters
for the water heater.
• Verify that the water heater is piped properly into the
heating system. Refer to Section 5 - System Piping
for the proper piping methods for the Shield water
heater.
• Check for 120 VAC to the water heater pump motor
on a call for heat. If voltage is not present, check the
wiring back to the main control board. Replace the
main control board if necessary.
Temp O/Shoot
• If 120 VAC is present on a call for heat and the water
heater pump is not operating, replace the pump.
• Verify that the water heater pump is set to the proper
speed or that the pump is the proper size.
Reference Section 5 - System Piping for water heater
pump specifications.
• Verify that the system is full of water and that all air
has been properly purged from the system.
Heat exchanger outlet water temperature
has exceeded the maximum outlet water
temperature.
• Verify that the water heater is piped properly into the
heating system. Refer to Section 5 - System Piping
for the proper piping methods for the Shield water
heater.
• Check for 120 VAC to the water heater pump motor
on a call for heat. If voltage is not present, check
wiring back to the main control board. Replace the
main control board if necessary.
• If 120 VAC is present on a call for heat and the water
heater pump is not operating, replace the pump.
• Replace the main control board.
70
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12 Troubleshooting
(continued)
Table 12E (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater
Interface
FAULT
DESCRIPTION
CORRECTIVE ACTION
Parameters
Progr
After downloading parameters from a laptop,
the main control board must be reset.
• Press the ENTER/RESET button on the display
panel.
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
• Check condensate tube from unit to floor drain for
proper installation and obstructions.
Blocked Drain
• Inspect condensate trap for blockage. Clean if
necessary.
The blocked drain switch has detected
excessive condensate build up inside the
unit.
SW
(will retry after 5
minutes. RESET may be
pressed after condition is
corrected.)
• Check for loose wiring connection at wire harness
plug.
• Bad blocked drain switch. Replace switch.
• Establish a draw to remove HW heat from the
water heater.
• Verify that the system is full of water and that all air
has been properly purged from the system.
• Verify that the water heater is piped properly into the
heating system. Refer to Section 5 - System Piping
for the proper piping methods for the Shield water
heater.
While the unit is in Service Mode, the outlet
temperature has exceeded 185°F.
• Check 120 VAC to the water heater pump motor on
a call for heat. If voltage is not present, check the
wiring back to the main control board. Replace the
main control board if necessary.
Service Blk
• If 120 VAC is present on a call for heat and the water
heater pump is not operating, replace the pump.
• Verify that the water heater pump is set to the proper
speed or that the water heater pump is the proper
size. Reference Section 5 - System Piping for water
heater pump specifications.
• Check 120 VAC supply to the transformer.
• Check wiring connections at the low voltage terminal
strip.
120 VAC input to the main control board has
dropped below 80 VAC.
Low 24 VAC
• Check the wire size/length to remote devices.
• Replace the transformer.
Watch Dog Error
The main control board has detected an
internal fault.
• Replace the main control board.
The main control board has detected an
internal fault.
• Replace the main control board.
• Replace the main control board.
Write EEProm
The main control board has detected an
internal fault.
CRC Parameters
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12 Troubleshooting
Combustion Analysis Procedure
Table 12G Flue Products
1. Press the SHUTDOWN button on the display until
Natural Gas
Propane
HTR:Off appears in the display window.
CO2
O2
CO2
9.0% - 11%
O2
2. Remove the screws securing the top panel to the unit.
Remove the panel from the unit to gain access to the flue
sensor.
8.0% - 10%
3.0% - 6.5%
4.1% - 6.9%
8. Once the combustion analysis is complete, press the
SHUTDOWN button on the display board (FIG. 10-1)
to take the water heater out of Service Mode. The
water heater will go to shutdown and the display will
show HTR:Off.
3. Locate the flue sensor in the top of the vent connection.
Remove the flue sensor and grommet from the unit. Note:
Combustion measurements will be made at this point.
4. Press the SHUTDOWN button on the display until
HTR:Standby appears in the display window.
9. Replace the flue sensor and grommet into the vent
connection.
5. Locate the pinhole button above the “r” in the Lochinvar
logo on the display board (FIG. 10-1). Insert a thin wire
(such as a paper clip) into the hole and press the button
once and hold for 5 seconds to place the water heater into
Service Mode. In Service Mode the water heater will fire at
ignition speed and will then modulate up to full fire.
10. Replace the top panel on the unit.
11. Place the Shield water heater back into normal operation.
You must replace the flue sensor to
ƽ WARNING
prevent flue gas spillage into the room.
Failure to comply could result in severe
personal injury, death, or substantial
property damage.
6. Insert the probe from a combustion analyzer into the hole
left by the removal of the flue temperature sensor.
7. Once the water heater has modulated up to full fire, measure
the combustion. The values should be in the range listed in
Table 12G. The CO levels should be less than 150 ppm for a
properly installed unit.
If the combustion is not within the specified range, reference
the chart below for possible causes and corrective actions.
Table 12F Troubleshooting Chart - Combustion Levels
POSSIBLE CAUSE
CORRECTIVE ACTION
• Refer to Section 2 - General Venting for the proper venting and air intake methods for the
Shield water heater.
Vent/Air Intake Length
or Obstruction
• Check for obstructions at the vent/air intake terminals.
• Refer to Section 7 - Gas Connections for the proper gas supply for the Shield water heater.
Gas Supply Pressure
• Refer to page 60 of this manual for burner removal and cleaning procedures.
• Replace burner if necessary.
Dirty/Damaged Burner
Gas Valve Adjustment
• Refer to page 73 of this manual for the gas valve adjustment procedure.
72
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(continued)
Gas valve adjustment procedure
If adjustment of the gas valve is deemed necessary, use the
following procedures: (Note: The procedures below are
model specific.)
Figure 12-3 Gas Valve Adjustment: Model SNA400-125
Models SNR150-100 -- SNA285-125
Locate the throttle adjustment screw on the side of the
venturi valve (FIG. 12-2). Using a screwdriver, turn the screw
a 1/4 turn clockwise to decrease CO2 levels or a 1/4 turn
counterclockwise to increase CO2 levels. After performing
one adjustment on the valve, follow the Combustion Analysis
Procedure on page 72 of this manual to measure the
combustion.
If combustion is still not within the specified range, repeat
the procedure. This procedure SHOULD NOT be performed
more than four (4) times. If after four (4) adjustments and
the combustion is still not within the specified range, revisit
the possible causes in Table 12F on page 72 or replace the
gas valve.
THROTTLE
ADJUSTMENT
SCREW
Model SNA500-125
Figure 12-2 Gas Valve Adjustment: Models
Locate the throttle adjustment screw on top of the gas valve,
see FIG. 12-4. Using a screwdriver, turn the screw a 1/4 turn
counterclockwise to increase CO2 levels or a 1/4 turn clockwise
to decrease CO2 levels. After one adjustment on the valve, follow
the Combustion Analysis Procedure on page 72 of this manual
to measure the combustion.
SNR150-100 -- SNA285-125
If combustion is still not within the specified range, repeat
the procedure. This procedure SHOULD NOT be performed
more than four (4) times. If after four (4) adjustments and the
combustion is still not within the specified range, revisit the
possible causes in Table 12F on page 72 or replace the gas valve.
THROTTLE
ADJUSTMENT
SCREW
Figure 12-4 Gas Valve Adjustment: Model SNA500-125
Model SNA400-125
Locate the throttle adjustment screw on the top of the gas
valve, see FIG. 12-3. Using a screwdriver, turn the screw 1/8
turn counterclockwise to increase CO2 levels or 1/8 turn
clockwise to decrease CO2 levels. After one adjustment on
the valve, follow the Combustion Analysis Procedure on page
72 of this manual to measure the combustion.
THROTTLE
ADJUSTMENT
SCREW
If combustion is still not within the specified range, repeat
the procedure. This procedure SHOULD NOT be performed
more than four (4) times. If after four (4) adjustments and
the combustion is still not within the specified range, revisit
the possible causes in Table 12F on page 72 or replace the gas
valve.
73
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13 Diagrams
Figure 13-1 Ladder Diagram
JUNCTION BOX
120VAC
NEUTRAL
GROUND
TERMINAL STRIP
120V SUPPLY "L"
TERMINAL STRIP
120V SUPPLY "N"
GND
PUMP
DHW
PUMP "L"
DHW
PUMP "N"
RELAY
4
3
DHW
PUMP
TERMINAL
STRIP
TERMINAL
STRIP
INTEGRATED CONTROL
F5
PUMP
X1-6
X1-8
RELAY COIL
X1-3
X1-1
2
1
5A
DHW PUMP
RELAY
BOX DEPICTS
OPTIONAL ITEMS
BLOWER
F4
1
2
LOW VOLTAGE
120 VAC
HIGH VOLTAGE
JUNCTION
BOX
3.5A
BLOWER
RELAY
3
F3
1.25A
X1-5
X6-8
120 VAC
JUNCTION BOX
CN2-4
CONNECTION
BOARD
F2
X5-7
24 VAC
X6-7
X6-2
3.5A
X6-3
CN2-10
CONNECTION
BOARD
CN5-1
CN5-2
CN5-4
CN2-6
INTEGRATED
CONTROL
LWCO
CN5-3
CN2-11 X6-9
CN2-12
LOW GAS
PRESSURE
SWITCH
HIGH GAS
PRESSURE
SWITCH
CONNECTION
BOARD
MANUAL RESET
HIGH LIMIT
X6-4
CN2-5
CN4-6
CN4-3
X5-14
CN2-3
X6-5
INTEGRATED
CONTROL
INTEGRATED
CONTROL
DISPLAY
EXTERNAL
LIMIT
2
1
CN2-9
X6-10
X3
AIR PRESSURE
SWITCH
RIBBON CABLE
X5-11
X5-4
X5-3
PC
X8
INTERFACE
BLOCKED
X5-8
X5-1
DRAIN
SWITCH
S2
S1
S3
INLET
SENSOR
AUTO RESET
HI-LIMIT
O-TEMPHEX SW
X5-10
X2-2
X2-1
OUTLET
SENSOR
GAS VALVE
BLOWER
X5-2
X5-9
FLUE
SENSOR
GAS VALVE
RELAY
CONNECTION BOARD
1
2
4
5
X5-5
X5-13
X5-6
CN4-11
CN4-12
X3-1
X3-3
RUN-TIME
CONTACTS
3
4
CN4-10
CN4-4
X3-4
X3-2
X5-12
ALARM
CONTACTS
5
6
TR1
X1-7
FLAME ROD
SPARK
ROD
CN4-1
CN4-4
CN3-8
CN3-6
X4-8
X4-6
S4
TANK
SENSOR
CAUTION HIGH VOLTAGE SPARK LEAD
CN4-5
CN4-2
CN3-10 X4-10
CN3-4 X4-4
+
-
EXTERNAL
CONTROL
0-10V
NOTES:
1. Where possible, switches are shown without utilities (gas, water or electricity) connected to the unit. As such, actual switch states may
vary from those shown on diagrams depending upon whether utilities are connected or a fault condition is present.
2. See wiring diagram for additional notes.
LADDER DIAGRAM
LBL20026 REV C
74
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TM
Installation & Service Manual
13 Diagrams
(continued)
Figure 13-2 Wiring Diagram
LOW VOLTAGE
120 VAC
HIGH VOLTAGE
WARNING
DISCONNECT POWER
BEFORE SERVICING
DISPLAY
BOX DEPICTS
OPTIONAL ITEMS
INTEGRATED CONTROL
X3
JUNCTION
BOX
PC
X8
INTERFACE
OR
W
L
CONNECTION BOARD
N
DHW
PUMP
GND
W
CN2
X1-5
CN1
PUMP
RELAY
3
1
2
4
OR
BK
CN2-9
1
X6-10
EXTERNAL
LIMITS
CN2-3
2
X6-5
OR
BK
X1-3
X1-6
L
BK
W
L
N
120V
GND
GND
N
SUPPLY
TERMINAL STRIP
PR
PR
R
CN2-7
5
X3-4
X3-2
X3-1
X3-3
ALARM
CONTACTS
G
R
X1-8
X1-1
CN2-1
6
CN2-8
3
RUN-TIME
CONTACTS
R
CN2-2
4
R W
G
BLOWER
1
2
3
1 2 3 4
5
R
T
X5-5
X5-13
X5-6
W
CN5
BK
BL
PR
BL
X5-12
X5-7
CN5-1
CN5-3
CN5-4
CN5-2
X6-2
X6-7
CN2-6
CN2-12
CN2-11
CN2-4
24 VAC
COM
BL
GY
LOW
MANUAL RESET
HI-LIMIT
PR
OR/BK
WATER
BR
Y
X5-14
X6-9
X6-3
X6-8
CUT-OFF
AIR PRESSURE
SWITCH
OR
OR
Y
CN2-10
OR/BK
P
X5-11
X5-3
X5-4
BLOCKED
DRAIN
P
GAS
PRESSURE
SWITCH
CN4-3
CN4-6
OR
GY
OR
GY
P
AUTO RESET
HI-LIMIT
X6-4
CN2-5
O-TEMP HEX SW
X5-10
X5-8
BK
S2
INLET
SENSOR
R
S1
S4
X5-1
CN4-1
CN4-4
CN4-5
CN4-2
OUTLET
SENSOR
FLUE
SENSOR
TANK
SENSOR
CN3
CN3
X4
W
Y
S3
X5-2
X5-9
+
-
EXTERNAL
CONTROL
0-10V
BK
Y
X2-2
X2-1
GAS
VALVE
CN4
FLAME
ROD
W/R
X1-7
TR1
G
SPARK
ROD
CAUTION HIGH VOLTAGE SPARK LEAD
Notes:
1. All wiring must be installed in accordance with: local, state, provincial and national code requirements per either N.E.C. in USA or C.S.A. in Canada.
2. If any original equipment wire as supplied with the appliance must be replaced, it must be replaced with wire having same wire gauge (AWG) and
rated for a minimum of 105°C. Exceptions: Repl acement high voltage spark lead and ribbon cables must be purchased from the factory. Use of a
non-approved spark lead or ribbon cables can lead to operational problems which could result in non-repairable damage to the integrated controller or
other components.
3. Actual connector block locations may vary from those shown on diagrams. Refer to actual components for proper connector block locations when
using diagrams to troubleshoot unit.
WIRING DIAGRAM LBL20025 REV C
75
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Revision Notes: Revision A (ECO #C02299) initial release.
Revision B (ECO #C02870) reflects the addition of a mixing valve to the
piping diagrams (FIG.’s 6-2 and 6-3, pgs. 32 - 34).
Revision C (ECO #C02738) reflects edits made to the Gas Valve
Adjustment Procedure for Model SNA400-125 on page 69.
Revision D (ECO #C03223) reflects edits made to the high altitude
section on page 7.
Revision E (ECO #C03735) reflects the addition of stainless steel
venting, hydro changes and the addition of the Anode Rod(s) section.
Revision F (ECO #C03974) reflects Delta T updates and additions.
Revision G (ECO #C05457) update the vent table to reflect Schedule
80 as acceptable CPVC material (R02799), reflects the addition of
the illustrations disclaimer on all the piping drawings (ECR #R02431),
add stainless steel as acceptable material in a closet or alcove
installation (R02900), add flex-smooth wall to the FasNSeal material
(ECR #R02845), add the left side service clearance dimensions, and
update the HEX cleaning procedure to reflect the new HEX cleaning kit
(R02634).
Revision H (ECO C06485) reflects the addition of required amperage
rating (15 amp) to the “Power Cord Connection” section on page 43
as well as the update of the piping diagrams on pages 36 - 38 and the
addition of Figure 12-3 on page 61 with a new notice about rope gasket
on heat exchanger door. Clearances from hot water pipe have also been
updated on page 8 within the “Clearances from combustible materials”
section, as well as Figures 1-1 and 1-2 on page 9. Table 2A on page
18 was also updated.
Revision I (ECO C07981) reflects the addition of the O-temp switch.
Revision J (ECO #C09803) reflects the addition of the new Polypropylene
Vent material section, rearranging the vent section, additional information
added to the humidity warning on page 8, edits made to the O-Temp
switch definition on page 4, addition of the AHRI and ASME logos
(R05009), along with the addition of the note on pg. 46 to not install the
neutralization kit horizontally (ECR R04791).
Revision K (ECO #C10143) reflects the removal of the “GV/RELAY
FAIL” FAULT (ECR #R05239) and updates made to the ignition timing
information.
SWH-I-S Rev K
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04/12
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