Water heaters for use with Natural and L.P.G.
GWH-635-ES
Temperature Modulated with Electronic Ignition
Suitable for heating potable water only - Not approved for space heating purposes
(Intended for variable flow applications with multiple tapping points)
GWH-635-ES-N
GWH-635-ES-L
Warning: If the information in this manual 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
vapor and liquids in the vicinity of this or any other
appliance.
What to do if you smell gas
• Close gas valve. Open windows.
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any
phone in your building.
• If you cannot reach your gas supplier, call the fire
department.
Improper installation, adjustment, alteration,
service or maintenance can cause injury or
property damage. Refer to this manual. For
assistance or additional information consult a
qualified installer, service agency or the gas
supplier.
• Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions
• Installation and service must be performed by a
qualified installer, service agency or the gas supplier.
In the Commonwealth of Massachusetts this
product must be installed by a licensed plumber or
gas fitter.
Upon completion of the installation, these
instructions should be handed to the user of the
appliance for future reference.
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Warning
Warning: Field wiring connections and
electrical grounding must comply with
local codes, or in the absence of local
codes, with the latest edition of the
National Electric Code, ANSI/NFPA 70,
or in Canada, all electrical wiring must
comply with the local codes and the
Canadian Electrical Code, CSA C22.1
Part 1.
Warning: Shock hazard line voltage is
present. Before servicing the water
heater, turn off the electrical power to
the water heater at the main disconnect
or circuit breaker. Failure to do so could
result in severe personal injury or death.
What to do if you smell gas
• Close gas valve. Open windows.
• 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 neighbor’s
phone. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire
department.
Fig. 1
• Installation and service must be performed by a
qualified installer, service agency or the gas supplier.
Warning: The heater must be
disconnected from the gas supply
piping system during any pressure
testing of that system at test pressures
equal to or more than 0.5 psig.
FCC:
This device complies with Part 15 of the FCC rules.
Operation is subject to the following two conditions: (1)
This device may not cause harmful interference, and (2)
this device must accept any interference received,
including interference that may cause undesired
operation.
Caution:
Any
changes
or
modifications not expressly approved
by the party responsible for compliance
could void the user’s authority to
operate the equipment.
Fig. 2
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2
Appliance details
Maximum input
2.1 Features
175,000 Btu/h (51.2 kW)
Parts
Efficiency in %
• Touch Pad interface control
Recovery efficiency 86.5%
• High power pre-mix compact burner with low Nox
emissions
Min. Output
• Modulating Gas Valve with constant gas:air ratio
control
31,131 Btu/h (9.1 kW)
Temperature Control
• Modulating water valve for improved comfort and
temperature control.
Selection range: 100°F (38°C) - 140°F (60°C)
Default temperature: 122°F (50°C)
Stability: +/- 2°F (+/- 1°C)
Safety
• Flame sensor (ionization) rod
• Overheat sensor
• Temperature limiter
• Fan speed monitoring.
Gas Requirement
Gas connection (inches) - ¾”
Inlet gas pressure under operation (with a high hot
water flow rate)*
High Quality Materials for Long Working Life
• Copper heat exchanger
• Propane: 11” - 14” water column
• Natural Gas: 5” - 14” water column
• Ceramic Burner output
• Gas pressure measuring point inside the appliance
at the gas valve inlet.
• Automatic overheating protection shut-off sensor
• Compact space saver: mounts on a wall with a
supplied bracket.
* Testing with a manometer, operate other gas
equipment on the same gas supply. Gas pressures
lower than 5" W.C. for Natural Gas or 11" W.C. for
LPG will result in insufficient degree rise to the hot
water being used. See Measuring Gas Pressure,
chapter 2.12.
• Easily removable one-piece cover.
Features
• LCD Display
• On/Off and Temperature control switches
• Reset button
• Program Key (Selectable temperature default)
• Failure codes for easy diagnostic and repair.
Accessories
• Optional wireless remote control accessory to
operate with the appliance
• Vent termination kit.
BOSCH is constantly improving its
products, therefore specifications are
subject to change without prior notice.
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Fig. 3 Gas pressure measuring point
Venting
2.2 GWH-635-ES Specifications
(Technical data)
See chapter 2.9 for Venting on page 9.
Water
Approved in US/Canada
• Hot water connection (inches) - ¾”
• Cold water connection (inches) - ¾”
Capacity
Maximum flow rate: 6.35 GPM (24 l/min) at a 45°F
(25°C) rise.
• Water valve material: Polymer (PPS) (Polypropylene
Sulfid)
Maximum output
• Minimum water flow: 0.8 gallon/minute (3 l/m)
142,968 Btu/h (41.8 kW)
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• Minimum recommended water pressure: 30 PSI
(2.07 bar)
UNPACKING THE GWH-635-ES HEATER
This heater is packed securely.
The box includes:
• Connections:
– Bottom of heater
• Pressure relief valve
Combustion
• Bracket for wall hanging the heater
• NOx ≤ 55 ppm
• Exhaust vent adaptor (with 4 screws and gasket
provided)
• CO ≤ 250 ppm
• Combustion air inlet adaptor (with 3 screws and gas-
ket provided)
• CO2 level set from factory, see chapter 9.1.
Dimensions
• Plastic decal shields for covering front cover screws
and control panel, installer should affix these decals
to the front of the unit after installation is complete.
See Fig. 4
• Depth (in): 8 ½” (220 mm)
• Width (in): 15 ¾” (400 mm)
• Height (in): 23 ½” (600 mm)
• Weight: 47 pounds (21 kg).
• Installation manual
• Product registration card.
Gas types
Do not lose this manual. Please complete and return
the enclosed product registration card.
Natural Gas.
LP Gas.
Before installing the unit, be certain you have the
correct heater for your type of Gas - Propane or
Natural Gas. Identification labels are found on the
shipping box, and on the rating plate which is located on
the right side panel of the cover.
Converting the gas type can only be done by a certified
gas technician with a calibrated CO2 analyzer. Call
CEC for conversion instructions.
Voltage
120 V AC (50/60 Hz)
To remove front cover
Amperage
• Loosen the two Philips head screws located on front
panel (beneath plastic decal shields if they are
already attached, see Fig. 4)
IDLE - 40 mA
Operation - ≤ 2,5 A
• Lift front cover panel upward and remove.
Noise
≤ 50 db (A)
Safety devices
• Flame failure device (ionization flame rod sensor)
• Pressure relief valve (supplied with heater)
• Over heat prevention (temperature limiter).
Plastic decals
Water resistant
IP X4 (protection against water drops)
Fig. 4 Remove front cover
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2.3 Dimensions and Minimum installation clearances
Fig. 5 Dimensions
1
2
3
4
5
6
Cover
On/Off switch
Reset button
LCD display
Program button
Temperature buttons
Fig. 6 Minimum clearances
Model GWH-635-ES
12”
TOP (A)
FRONT (B)
BACK
4”
0”
SIDES
4”
FLOOR (C)
12”
VENT DIAMETER
3”
Table 1 Minimum clearances
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2.4 General rules to follow for safe
operation
2.5 Proper location for installing your
heater
B 1. You should follow these instructions when you
install your heater. In the United States: The
installation must conform with local codes or, in the
absence of local codes, the National Fuel Gas Code
ANSI Z223.1/NFPA 54.
Carefully select the location of the water heater. For
your safety and for proper heater operation, you must
provide combustion air to the heater and a proper
exhaust vent system.
Follow the guidelines below:
In Canada: The Installation should conform with
CGA B149.(1,2) INSTALLATION CODES and /or
local installation codes.
B 1. Locate the heater where venting, gas and
plumbing connections are feasible and convenient.
B 2. It is strongly recommended that the heater be
installed as a ROOM SEALED heater (twin pipe). If
the heater will be installed as an UNSEALED heater
(single pipe) than National building codes require
that you do not install this appliance in bathrooms,
bedrooms or any occupied rooms normally kept
closed. Heaters that are UNSEALED require a
considerable amount of combustion air, see
chapter 2.8. If installing the heater UNSEALED
within a laundry room, be certain that the dryer is
properly vented. Failure to properly vent a dryer could
result in a gradual accumulation of lint build up inside
the combustion chamber of the heater.
B 2. Carefully plan where you install the heater. Correct
combustion air supply and vent pipe installation are
very important. If not installed correctly, fatal
accidents can be caused by lack of air, carbon
monoxide poisoning or fire.
B 3. When the unit is installed indoors and ROOM
SEALED (twin pipe) it is permitted to be located in
bathrooms, bedrooms and occupied rooms that are
normally kept closed. See chapter 2.9. If the unit will
be installed indoors and use indoor combustion air,
the place where you install the heater must have
enough ventilation. The National Fire Codes do
not allow UNSEALED gas fired water heater
installations in bathrooms, bedrooms or any
occupied rooms normally kept closed. See
chapter 2.5 and 2.8.
B 3. The hot water lines should be kept short to save
energy. Centrally locating the water heater is best. It
is always best to have hot water lines insulated.
B 4. You must vent your heater. See section on
Warning: The water in this water
heater is cold and always remains cold
except for the times that hot water is
being used DO NOT INSTALL IN AN
AREA WHERE IT COULD FREEZE.
Drain the heater entirely if freezing
temperatures are anticipated in area
VENTING.
B 5. The appliance must be isolated from the gas
supply piping system by closing its individual manual
gas shutoff valve (not supplied with heater) during
any pressure testing at pressures in excess of ½ Psig
(3.5 kPa).
The appliance and its gas connection must be leak
tested before placing the appliance in operation.
where
heater
is
installed
by
disconnecting both the inlet and outlet
connections at the bottom of heater.
To prevent any freeze damage,
introduce short bursts of compressed
B 6. Keep water heater area clear and free from
combustibles and flammable liquids. Do not locate
the heater over any material which might burn.
air
(20-40psi)
through
these
B 7. Correct gas pressure is critical for the optimum
operation of this heater. Gas piping must be sized to
provide the required pressure at the maximum output
of the heater, while all the other gas appliances are in
operation. Check with your local gas supplier, and
see the section on connecting the gas supply.
connections to remove the residual
water in the horizontal pipes and water
valve.
Warning:
Flammable
materials,
B 8. Should overheating occur or the gas supply fail to
shut off, turn off the gas supply at the manual gas
shut off valve, on the gas line. Note: manual gas
shutoff valve is not supplied with the heater.
gasoline, pressurized containers, or any
other items or articles that are potential
fire hazards must NOT be placed on or
adjacent to the heater. The appliance
area must be kept free of all
combustible materials, gasoline and
other flammable vapors and liquids.
B 9. Do not use this appliance if any part has been
underwater. Immediately call a qualified service
technician to inspect the appliance and to replace
any part of the control system and any gas control
which has been underwater
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2.6 Clearances
The GWH-635-ES is design certified for installation on
a combustible wall (see 2.7 Mounting installation)
provided the floor covering below the heater is
noncombustible. For installations in an alcove or closet,
maintain the minimum clearances to combustible and
non-combustible materials listed below. See also Fig. 6.
A. Top 12 inches (306 mm)
B. Front 4 inches (102 mm)
C. Back 0 inches
D. Sides 4 inches (102 mm)
E. Bottom 12 inches (306 mm)
Clearances from any exhaust vent pipe are dependent
upon the clearance requirements of the stainless steel
vent pipe manufacturer. Single wall stainless steel
(AL29-4C) vent pipe (vent type rated for Category III
appliances) must be used when exhaust venting this
appliance. See 2.9 Venting.
2.7 Mounting installation
Warning: before starting installation:
Fig.
7Mounting
the
heater
B check that there are no loose parts
inside the appliance
2.8 Combustion air requirements
B ensure that gas pipe, gas valve, mixer,
fan and burner have no damage and are
properly fitted.
The GWH-635-ES is a sealed water heater and it is
recommended that outdoor combustion air be piped to
the unit. When combustion air is piped to the unit
(TWIN PIPE SYSTEM) the combustion air pipe system
may be constructed of either 3" PVC, aluminum or
galvanized pipe. See Fig. 11,12 and 13. Select a point
for building penetration being sure that the necessary
clearance on the outside of the building, between the
combustion air pipe and the exhaust vent terminator of
the appliance, can be maintained, see Fig. 16. NOTE:
Observe all local building codes when penetrating a
building wall.
NOTE: The combustion air inlet location on the
side of a building must never be less than 3 feet
away from the units exhaust vent terminator, see
Fig. 16 Table 3.
The heater has the ability to operate without
combustion air being piped to it from the outside,
provided there is an adequate amount of combustion air
available in the room area. Observe the following
instructions concerning combustion air when following
the SINGLE PIPE (exhaust venting only) SYSTEM only
and follow Fig. 14 and 15 for proper setup.
Front cover should be removed (see
instructions on page 4) in order to inspect
components visually.
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The GWH-635-ES is design certified for mounting on a
wall. Secure the wall mounting bracket provided with
the heater to a wall surface. See Fig. 7.
Do not install this appliance on a carpeted wall or over
floor covering which is combustible, such as carpet.
The heater must be mounted on a wall using
appropriate anchoring materials.
If the mounting bracket is unable to line up on two wall
studs it is recommended that support board(s), either
1x4's or ½" (minimum) plywood first be attached across
a pair of studs and then the heater should be attached
to the support boards. The heater should be kept level
on the wall surface. See Fig. 7.
Expansion and contraction of piping due to changing
water temperature in the pipes imparts movement to the
heater which, if mounted directly to a brittle, friable
board, such as plasterboard, can cause failure of
mounting.
• Appliances located in unconfined spaces:
– a) An unconfined space is one whose volume is
greater than 50 cubic feet (1.42 cubic meter) per
1000 Btu per hour (292.81 Watts) of the
combined rating of all appliances installed in the
space. That would be 8750 cubic feet (247.8
cubic meter) for the GWH-635-ES alone.
Before installing the unit, be certain you have the
correct heater for your type of Gas - Propane or
Natural Gas. Identification labels are found on the
shipping box, and on the rating plate which is located on
the right side panel of the cover.
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– b) In unconfined spaces in buildings of
conventional frame, masonry, or metal
Establish vent clearances that comply with the vent
manufacturer's specifications. In all cases follow local
codes. See table 2.
construction, infiltration air is normally adequate to
provide air for combustion.
• Appliances located in confined spaces:
The confined space must be provided with two
permanent openings, one commencing within 12
inches (304.8mm) of the top and one commencing
within 12 inches (304.8mm) of the bottom of the
enclosure. Each opening must have a minimum free
area of one square inch per:
– 1000 Btu/hr (292.81 Watts) if all air is taken from
inside the building
– 2000 Btu/hr (585.62 Watts) if all air is taken from
the outside by horizontal ducts
– 4000 Btu/hr (1171.24 Watts)if all air is taken from
the outside by direct openings or vertical ducts
Or the confined space must be provided with one
permanent opening or duct that is within 12 inches
(304.8mm) of the ceiling of the enclosure. This opening
must have a minimum free area of one square inch per:
– 3000 Btu/hr (878.43 Watts) if all air is taken from
the outside by a direct opening or vertical duct.
Louvers, grills and screens have a blocking effect. If the
effective free area is not known, increase the sizes of
your openings by 75% if your louvers are wood and by
30% if your louvers are metal. Refer to the National Fuel
Gas Code for complete information. In buildings of tight
construction all air should be taken from outside.
2.9 Venting
Warning: Do not reduce the vent
(exhaust and combustion) pipe sizes
and do not common vent with any other
vented appliance or stove.
NOTE: This appliance's exhaust must be vented
to the outside with a sealed 3" stainless steel
vent pipe (AL29-4C). The appliance's flue gasses
are under positive pressure and must travel
through a stainless steel 3" pipe that is sealed
gas tight. Stainless steel vent pipe is equipped
with sealing gaskets for ease of installation,
proper safety and durability. The heater shall not
be vented in combination with any other
appliance; the appliance must only be vented
with a dedicated sealed vent system.
Caution: The vent system must be
installed by a qualified agency in
accordance with these instructions. If
improperly installed
a
hazardous
condition such as explosion or Carbon
Monoxide poisoning could result. CEC
will not be responsible for improperly
installed appliances.
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The maximum flue gas exhaust temperature on the GWH-635-ES is 437°F (225°C)
Venting
Options
Exhaust
vent
diameter
and
* Exhaust
vent
maximum
length
* Exhaust Combustion Combustion Vent pipe
Vent pipe
clearances
within an
enclosed
space
vent
air pipe
air pipe
clearances
within an
unenclosed
space
minimum
length
diameter
and material length
maximum
material
Room
sealed
(twin pipe)
3 inch
stainless
steel
(AL29-4C)
sealed vent
pipe
26 feet (8
m) with one
elbow. Less
2½ feet for
each
3 feet
3 inch PVC,
aluminum or
galvanized
pipe
26 feet (8
** See vent
manufacturer's manufacturer's
specifications
** See vent
m) with one
elbow. Less
2½ feet for
each
additional
90° elbow
specifications
additional
90° elbow
Open
3 inch
stainless
steel
(AL29-4C)
sealed vent
pipe
26 feet (8
m) with one
elbow. Less
2½ feet for
each
3 feet
See
chapter 2.8
See
chapter 2.8
** See vent
manufacturer's manufacturer's
specifications specifications
** See vent
combustion
(single
pipe)
additional
90° elbow
Exhaust vent is always fan assisted. Installation of exhaust vent and combustion air piping may be run vertically or horizontally
and in separate directions if required.
* A maximum of three 90 degree elbows are permitted in the total vent length. The total vent length must be reduced by 1 ¼
feet for every 45° elbow used in the vent system.
** Stainless steel (AL29-4C) vent pipe is manufacturerd by Z-Flex, Protech and Heat Fab. NOTE: clearance distances are
variable depending if the vent pipe is installed in an enclosed or unenclosed space, the exhaust flue gas temperature and the
orientation of the vent pipe.
Table 2
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The appliance should be located as close to the point
of termination as possible. The maximum vent length is
26 feet (8 m) with one 90 degree elbow. Subtract 2½
feet from the total vent length for each additional 90°
elbow used (a maximum of three 90° elbows are
permitted in the total vent length), or subtract 1 ¼ feet
for every 45° elbow used. Horizontal sections of vent
must pitch ¼" for every foot of horizontal length and be
supported at 4 foot intervals with overhead hangers.
Any vent section greater than 45 degrees is considered
an elbow.
Vent Safety System
The GWH-635-ES will shut down if inadequate exhaust
venting is detected or a lack of combustion air is
provided to the unit; see troubleshooting section on
page 24. See error code to confirm error, correct the
problem and then reset the heater before operating.
Attaching the exhaust and air inlet connection
adaptors to the top of the heater
Note: The stainless steel exhaust vent pipe should not
be used in concealed or unheated locations. Listed
thimbles or collars are necessary to pass through wall
and ceiling partitions. If the vent system passes through
combustible areas where the vent clearance
requirements cannot be maintained, it is permissible to
chase straight sections of sealed 3 inch single wall vent
through 4 inch (or greater) Type-B vent. The distance to
combustibles using this chase technique is 1 inch.
Note: Type-B vent should never be used as the
actual exhaust vent system for the appliance, as
it is not gas tight.
Fig. 10
Minimum exhaust vent size and length
The use of a 90 degree elbow
is equivalent to 2 ½ ft in vent
length.
The use of 45 degree elbow is
equivalent to 1 ¼ ft in vent
length.
Fig. 11
B Attach the flue gas exhaust accessory (8 705 504
114) to the top of the unit (position 1) using the 4
screws and gasket provided, and fully insert 3"
stainless steel vent pipe into the accessory and
tighten the clamp (position 2).
Fig. 8
Maximum exhaust vent and combustion air inlet
lengths
B Attach the combustion air inlet accessory (8 705
504 115) to the top of the unit (position 3) using the
3 screws and gasket provided, and fully insert 3"
combustion air pipe into the accessory and tighten
the clamp (position 4). NOTE: The appliance has the
possibility to mount the combustion air inlet
accessory on the top right or on the top left side of
the heater. The combustion air inlet that is not used
must be kept sealed.
2.9.1 Venting options
Installing this water heater as a room sealed (TWIN
PIPE SYSTEM) is the recommended method. Contact
CEC or dealer for available vent termination kits and
vent materials for this water heater.
Fig. 9
Note: reduce 2½ ft for each 90° elbow used after the
first one, reduce 1 ¼ ft for each 45° elbow.
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Open combustion installation (SINGLE PIPE
SYSTEM)
Exhaust venting shall be done with 3”
stainless steel (AL29-4C) vent pipe.
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Room sealed installation (TWIN PIPE SYSTEM)
Fig. 12
Fig. 14
Combustion air pipe: ≤ 26 ft (8 m)
Exhaust vent pipe: ≤ 26 ft (8 m)
Exhaust vent pipe: ≤ 26 ft (8 m)
A condensate trap (drain tee) must be used in any side
wall installation if the total exhaust vent length is greater
than or equal to 5 feet (1.5 m), see page 14.
A condensate trap (drain tee) must be used in any side
wall installation if the total exhaust vent length is greater
than or equal to 5 feet (1.5 m), see page 14.
Fig. 13
Fig. 15
Combustion air pipe: ≤ 26 ft (8 m)
Exhaust vent pipe: A+B+C ≤ 23½ ft (7.2 m)
A condensate trap (drain tee) must be used for any
vertical exhaust vent installation. The condensate trap
should be positioned as near to the top of the heater as
possible, see page 14.
Exhaust vent pipe: A+B+C ≤ 23½ ft (7.2 m)
A condensate trap (drain tee) must be used for any
vertical exhaust vent installation. The condensate trap
should be positioned as near to the top of the heater as
possible, see page 14.
The exhaust vent system must vent directly to the
outside of the building and an adequate amount of
indoor combustion air must be provided for this
installation. See chapter 2.8.
Note: reduce 2½ ft for each 90° elbow used after the
first one, reduce 1 ¼ ft for each 45° elbow.
A maximum of three 90-degree elbows are permitted.
Connecting a one piece 90 degree elbow pipe to the
combustion air inlet adaptor is recommended, this will
prevent debris or objects from ever falling into the inlet
opening.
Note: reduce 2½ ft for each elbow used after the first
one, reduce 1 ¼ ft for each 45° elbow.
The exhaust vent pipe and combustion air
pipe can be run vertically or horizontally.
i
Maximum length for each individual pipe is
26 feet (8 m) with one elbow, for each
additional 90° elbow after the first elbow
you must reduce 2½ feet from the total
vent length, or 1 ¼ feet for each 45°
elbow.
A maximum of three 90-degree elbows are permitted.
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Recommended exhaust vent terminator position
Fig. 16
Ref.
A
Description
Minimum distance
Directly below an opening; operable windows, doors and any non-
mechanical fresh air openings
36 in
Below a gutter, sanitary pipework or eaves
24 in
12 in
B
Below a gutter, sanitary pipework or eaves, protected by metal
shielding
C
From any internal corner
Above ground
12 in
12 in
7 ft
D*
Above a paved sidewalk or driveway
From an opposing wall or structure facing the termination
24 in
36 in
E
From any other building opening, gas utility meter, service regulator
or the like
F
From a terminator facing a terminator
48 in
60 in
G
Vertically between two exhaust vent terminators on the same wall
H
Horizontally between two exhaust vent terminators on the same wall
12 in
36 in
Horizontally from combustion air inlet of 635-ES
Vertically above or below combustion air inlet of 635-ES
From the combustion air inlet of any other equipment
From any external corner
I**
6 ft
J
12 in
Horizontally from an opening; operable windows, doors and any
non-mechanical fresh air openings
K
12 in
Vertically from a wall, roof slope, or obstruction (venting through a
flat or pitched roof)
see ABOVE THE ROOF
requirements on following page
L
Table 3
* Subject to local codes and anticipated snow level
** Other equipment that operates with a mechanical air inlet may require greater distances, reference manufacturer's instructions
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Supporting the exhaust vent system and the use
of an external condensate trap
External condensate traps
B A condensate trap must be used in any sidewall
exhaust vent installations when the total vent length
is ≥ 5 ft (1.5 m) OR the vent pipe passes through an
unheated space (below 60F).
B A condensate trap must be used for any vertical
exhaust installations. See Drain Tee position options
in Fig. 19 and Fig. 20.
B When installing the condensate tube at the bottom of
the drain tee, be sure to form a trap by means of a 3"
(76.2 mm) loop filled with water. This tube must be
3/8" ID high temperature silicone for at least the first
6 inches (152 mm) and attached with a gear clamp
or hose clamp. The condensate must be disposed of
according to local regulations.
Fig. 18 Above the roof clearance requirements from
rain cap (combustion air piping not being
shown)
The venting materials and accessories
required to properly install the water
heater are available from CEC and their
distributors.
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Fig. 17Horizontal
side
wall
venting
installation
(combustion air piping not being shown)
A condensate trap (drain tee) must be used in any side
wall installation if the total exhaust vent length is greater
than or equal to 5 feet (1.5 m).
Fig. 19 Vertical venting installation (combustion air
piping not being shown)
A condensate trap (drain tee) must be used for any
vertical exhaust vent installation. The condensate trap
should be positioned as near to the top of the heater as
possible.
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2.10 Gas piping & connections
Before connecting the gas supply, check the rating
plate on the right side of the heater to be sure that the
heater is rated for the same gas to which it will be
connected.
In the United States: The installation must conform with
local codes or, in the absence of local codes, the
National Fuel Gas Code ANSI Z223.1/NFPA 54.
In Canada: The Installation should conform with CGA
B149 INSTALLATION CODES and/or local installation
codes.
GAS LINE SIZING
The gas supply piping should be sized according to the
Applicable Plumbing Code for a maximum draw of
175,000 BTUH. First determine the effective length of
the gas supply line by measuring the actual length of
piping, and then adding 5 ft. (1.52m) for every elbow or
“T” to the actual length. Use the charts in Fig. 22 to
determine the pipe diameter necessary to
accommodate the BTU (Wh) demand of the unit. If
there are more gas drawing appliances on the line, size
according to the maximum amount of BTU (Wh)
demand.
Note: It is important that if any flexible gas line is used,
above or below ground between the gas supply meter/
regulator and the water heater, that it be sized properly;
we recommend the use of non-corrugated flexible gas
line when used. Consult the gas sizing specification
tables provided by the flexible gas line manufacturer.
Fig. 20 Vertical venting installation
-
Masonry
Chimney (combustion air piping not being
shown)
A condensate trap (drain tee) must be used for any
vertical exhaust vent installation. The condensate trap
should be positioned as near to the top of the heater as
possible.
Inlet gas particle screen
Gas piping
Fig. 21
B Install a manual gas shut off valve, on the gas supply
line.
B The use of a union when connecting gas pipe to the
gas inlet connection is critical, this will facilitate any
necessary servicing and cleaning of the inlet gas
particle screen.
B Flexible gas line connectors are not recommended
because they are commonly undersized and restrict
gas flow. Oversize the diameter of any flexible gas
line connector if one must be used.
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FOR NATURAL GAS
Maximum Capacity of pipe in Cubic Feet of Gas per Hour for Gas Pressure of 0.5 Psig or less and a Pressure drop
of 0.3 in Water Column (0.75mbar).(Based on a 0.60 Specific Gravity Gas) Btu numbers given in thousands.
Follow boxed numbers for piping just one GWH-
635-ES (example: ¾” B.I. Natural Gas pipe for 20 ft
(6.1m). will handle 190,000 btu’s (55.7 kWh). For
multiple appliances combine the total btu input load
and then refer to applicable chart below.
Nominal
Iron
Length of Black Iron Pipe, Feet
Pipe
Internal
Size,Diameter
inches inches
10
20
30
40
50
60
70
80
90
100
125
150
175 200
1/4
3/8
1/2
0.364
32
72
22
49
92
18
40
73
15
34
63
14
30
56
12
27
50
11
25
46
11
23
43
10
22
40
9
8
8
7
6
0.493
0.622
21
38
18
34
17
31
15
28
14
26
132
3/4
1
0.824
1.049
278
520
190
350
152
285
130
245
115 105
96
90
84
79
72
64
59
55
215 195 180
170
160
150
130
120
110 100
1 1/4
1 1/2
2
1.380
1.610
2.067
2.469
3.068
4.026
1050
1600
3050
4800
8500
730
590
890
500
760
440 400 370
670 610 560
350
530
320
490
930
305
460
870
275
410
780
250
380
710
225 210
350 320
650 610
1100
2100 1650 1450
3300 2700 2300
5900 4700 4100
1270 1150 1050 990
2 1/2
3
2000 1850 1700 1600 1500 1400 1250
3600 3250 3000 2800 2600 2500 2200
1130 1050 980
2000 1850 1700
4
17,500 12,000 9,700 8,300 7,400 6,80 6,200 5,800 5,400 5,100 4,500 4,100 3,800 3500
Nominal
FOR LP GAS
Iron Pipe
Size,
Black Iron Pipe
Maximum Capacity of Pipe in Thousands of BTU per
Hour of Undiluted Petroleum Gases (at 11 inches
Water Column Inlet Pressure) (Based on a Pressure
Drop of 0.5 Inch Water Column).
Length of Pipe, Feet
Inches
10 20 30
40 50 60 70 80 90 100 125 150
1/2
275 189 152 129 114 103 96 89 83
78
69
63
3/4
1
567 693 315 267 237 217 196 185 173 162 146 132
107 732 590 504 448 409 378 346 322 307 275 252
1 1/4 220 149 121 103 913 834 771 724 677 630 567 511
1 1/2 330 229 185 155 141 127 118 108 102 976 866 787
2
622 433 346 299 264 239 220 204 192 1811 1606 1496
Copper
Length of Tubing, Feet
Maximum Capacity of Semi-Rigid (flexible, non
corrugated) Tubing in Thousands of BTU per Hour
of Undiluted Liquefied Petroleum Gases (at 11
inches Water Column Inlet Pressure).
Outside
Diameter,
Inch
10 20
39 26
92 62
30 40
21 19
50 41
50
_
60 70 80 90 100
3/8
1/2
_
_
_
_
_
37
79
35 31 29 27 26
72 67 62 59 55
(Based on a Pressure Drop of 0.5 Inch Water
Column)
5/8 199 131 107 90
3/4 329 216 181 145 131 121 112 104 95 90
7/8 501 346 277 233 198 187 164 155 146 138
* Source National Fuel Gas Code NFPA 54, ANSI
Z223.1 - No Additional Allowance is necessary for an
ordinary number of fittings
Fig. 22
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load. Using a manometer, then measure the inlet gas
pressure at the inlet gas pressure test port. See Fig. 23.
Gas pressures lower than 5" W.C. for Natural Gas or
11" W.C. for LPG will result in insufficient degree rise
to the hot water being used. See Gas Connections,
chapter 2.10.
2.11 Gas line sizing
B It is strongly recommended that the Natural Gas pipe
be Black Iron pipe the entire distance from the
outside meter to the inlet of the gas connection. ¾”
Black Iron pipe up to 20 feet (6.1m) and 1” Black Iron
pipe up to 70 feet (21.34m) distances. Flex line is
NOT recommended, but if used, then oversize the
diameter of the flex pipe, keep the length to a
minimum and try to keep the flex line as straight as
possible.
B It is strongly recommended that the LP Gas pipe be
semi-rigid copper or Black Iron pipe from the outside
regulator to the inlet of the gas connection. For semi-
rigid copper piping: 5/8” up to 10 feet (3.05m) and
¾” up to 30 feet (9.14m) distances. For Black Iron
piping: ½” up to 20 feet (6.1m) and ¾” up to 80 feet
(24.38m) distances. Flex line is NOT recommended,
but if used, then oversize the diameter of the flex
pipe, keep the length to a minimum and try to keep
the flex line as straight as possible.
Fig. 23 Gas pressure measuring (left tapping)
HIGH ALTITUDE OPERATION
Due to the lower density of air at high altitudes, output
must be reduced in installations above 4,000 ft (1,219
m).
THESE FIGURES ARE FOR GWH-635-
ES SUPPLY ONLY, ALL OTHER
APPLIANCES IN THE BUILDING MUST
BE INCLUDED IN THE PIPE SIZING.
i
Altitude
Natural Gas:
Liquid
Propane:
0 - 4,000 ft
(0 - 1,219 m)
no
National Fuel Gas Code requires that a sediment trap
(drip leg) be installed on gas appliances not so
equipped. Also, a manual gas shut off valve must be
installed on the gas supply line within close proximity of
the water heater and be visible from the water heater.
no modification
modification
4,000 ft - 8,000 ft
(1,219 m - 2,438 m)
contact CEC for detailed
instructions
Above 8,000 ft
Warning: The heater must be
disconnected from the gas supply
piping system during any pressure
testing of that system at test pressures
equal to or more than 0.5 psig.
(above 2,438 m)
Table 4
Burner output at altitudes greater than 4,000 ft (1,219
m) will be electronically reduced once the control board
has been properly adjusted.
The water heater must not be piped with gas supply
pressures in excess of 0.5 psig. If overpressure has
occurred, such as through improper testing of the gas
lines or malfunction of the supply system, the gas valve
must be checked for safe operation.
When connections are made, check for gas leaks at all
joints. Apply some soapy water to all gas fittings. Soap
bubbles are a sign of a leak.
Danger: If you have a leak, shut off the
gas. Tighten appropriate fittings to stop
leak. Turn the gas on and check again
with a soapy solution. Never test for gas
leaks using a match or flame.
2.12 Measuring gas pressure
To measure and verify if adequate gas pressure is being
delivered to the water heater, first run a high hot water
flow rate and operate other gas equipment on the same
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allows complete drainage of both the PRV and the line.
The location of the PRV must be readily accessible for
servicing or replacement, and be mounted as close to
the water heater as possible. See Fig. 25. To install the
PRV, a suitable fitting connected to an extension on a
“T” fitting can be sweated to the hot water line.
Support all piping.
2.13 Water connections
When facing the heater, the ¾” cold water inlet is on the
bottom right and the hot water outlet is on the bottom
left. Install the heater centrally in the building if possible
and make hot water piping runs as short as possible.
INLETFILTER
SCREEN
COLD
HOT
Fig. 24
Fig. 25 Plumbing Connections and Pressure Relief
Valve
B The use of a union when connecting both water
pipes to the inlet and outlet connections is
recommended, this will facilitate any necessary
servicing and required cleaning of the inlet water
particle screen.
Although water piping throughout the building may be
other than copper, we recommend that copper,
galvanized or suitably rated stainless steel flex line
piping be used for the water heater connections (follow
local codes if more stringent). Never sweat any rigid
piping directly to or beneath the water connections,
damage can occur to the internal water valve from
heating of the pipe. Plastics or other PEX type plumbing
line materials are not suitable for connecting directly to
the water heater. Keep water inlet and outlet pipes to no
less than ¾" (19.05mm) diameter to allow the full flow
capacity.
If the cold and hot connections to the heater are
reversed, the heater will not function. Be certain there
are no loose particles or dirt in the piping. Blow out or
flush the lines before connecting to the water heater.
Full port valves should be installed on both the cold
water supply and hot water outlet lines to facilitate
servicing the heater (see Fig. 25). For installation on a
private well system with the use of a pressure tank, the
lowest pressure range setting recommended is 30-50
psi (2.07 and 3.45bar).
Connecting the pressure relief valve (PRV)
A listed pressure relief valve supplied with the heater
must be installed at the time of installation. No valve is
to be placed between the PRV and the heater. No
reducing coupling or other restriction may be installed
in the discharge line. The discharge line must be a
minimum of 4” above a drain and installed such that it
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2.14 Electrical connections
2.16 For your safety read before
operating your water heater
Warning:
For
safety
reasons,
disconnect the power supply to the
heater before any service or testing is
performed.
Warning: If you do not follow these
instructions exactly, a fire or explosion
may result causing property damage,
personal injury or loss of life.
Warning: This heater must be
electrically grounded in accordance
with the most recent edition of the
National Electrical Code. NFPA 70. In
Canada, all electrical wiring to the
heater should be in accordance with
local codes and the Canadian Electrical
Code, CSA C22.1 Part 1. Do not rely
on the gas or water piping to ground the
metal parts of the heater.
A. This appliance is equipped with electronic ignition for
lighting the main burners. When turning the heater on,
follow these instructions exactly.
B. Before operating the unit, set the On/Off switch to
the On ( I ) position.
WHAT TO DO IF YOU SMELL GAS
B Do not try to light any appliance.
B Do not touch any electric switch; do not use any
phone in your building.
The GWH-635-ES requires an electrical power supply
from a 120VAC 60Hz circuit and must be properly
grounded.
A means for switching off the 120VAC power supply
must be provided.
B Immediately call your gas supplier from a neighbors
phone. Follow the gas supplier’s instructions.
B If you cannot reach your gas supplier, call the fire
department.
The heater is wired as shown in the wiring diagram
(chapter 6, Fig. 36).
C. Use only your hand to turn the on/off control switch.
Never use tools. Follow these instructions exactly. If
control switch is jammed, close the gas supply and call
a qualified service technician. Attempted forceful repair
may result in a fire or explosion.
D. Do not use this appliance if any part has been under
water. Immediately call a qualified service technician to
inspect the appliance and to replace any part of the
control system and any gas control which has been
under water.
2.15 Operating instructions
B Before proceeding with the operation of the heater
make sure that the system is filled with water.
B Turn off power supply to heater.
B Open the cold water inlet supply to the heater fully.
B Open a hot water faucet to permit the water to fill the
heater and the piping and to eliminate the air trapped
in the system.
2.17 Lighting and operating instructions
B Close the hot water faucet after the water flows freely
and all the air has escaped from the system. Turn on
power supply to heater. The water heater is now
ready to operate.
B 1. STOP! Read the previous safety information.
B 2. The gas valve must be shut off by putting the ON/
OFF switch to position (0). Wait five (5) minutes to
clear out any gas. If you smell gas, STOP! Follow “B”
in the safety information above. If you do not smell
gas, go to the next step.
NOTE: A default temperature setting of
122 F will appear on the display screen.
i
B 3. This appliance is equipped with electronic ignition
for lighting the main burners. When turning the
heater on, follow these instructions exactly.
B 4. Set the ON/OFF switch to the (I) position. In this
position, the water heater is ready to use.
B 5. Open a hot water tap.
B 6. The burners will remain on until the hot water tap
is turned off.
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NOTE: on a first time initial instal-
lation or after gas line work has
been done, existence of air in the
gas line will cause ignition delay
when the hot water is turned on.
This will result in an error (EA) on
the units display screen. This is
normal. When this occurs, leave
the hot water running and wait 3-5
seconds, then reset the unit (Fig.
26, pos. 2). Wait for (EA) to disap-
pear. The heater will begin to at-
tempt ignition again, if the (EA)
reappears then repeat this same
process until all air has been bled
from the gas line.
i
When the heater is in operation you will hear its power
vent fan and burner operating. Upon turning off the hot
water flow the power vent fan will continue to operate
for up to 60 seconds to exhaust all flue gases. The
power vents fan speed is variable depending on the rate
of hot water used and the burner output.
TO TURN OFF GAS TO APPLIANCE
B Turn off the manual gas shut off on the supply line to
the heater and set the ON/OFF switch to the OFF (0)
position. Note: a manual gas shut off valve is not
supplied with the heater.
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Operation instructions
3
Operation instructions
Fig. 26
1
2
3
4
5
6
On/Off switch
Reset button
Program Key
Increasing temperature selector
Decreasing temperature selector
LCD display
B Press buttons
and
in order to reach
requested temperature.
3.1 Power
On
B To start the appliance switch the button to position
(I).
LCD display the default temperature - temperature
factory setting 122°F (50°C).
Fig. 28
If the outlet water temperature is set too high, the heater
can produce temperatures that are too hot. A
temperature balance shower valve can automatically
mix in cold water to reduce such hot water temperature.
In the event of any temperature instability with the use
of a temperature balance shower valve, refer to shower
valve manufacturer's instructions for internal adjustment
setting. Adjustments should be made to the hottest
setting in the shower valve. Additionally the temperature
control of the heater can be lowered to produce a more
comfortable hot water temperature.
Fig. 27
Off
B To shut down the appliance switch the button to
position (0).
3.2 Temperature selection
To select water temperature outlet:
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Operation instructions
Setting the water temperature
The desired temperature of the hot water can be adjusted on the front control panel of the heater.
The GWH-635-ES has an electronically controlled gas valve that modulates the burner input in response to both
varying hot water flow rates and/or changes in any incoming and outgoing water temperatures.
Hot Water Flow and Temperature with Various Inlet Temperature (gpm/Fahrenheit)
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
90
100
110
120
130
140
150
Hot water temperature (ºF)
Inlet (ºF) 40
Inlet (ºF) 50
Inlet (ºF) 60
Inlet (ºF) 70
Hot Water Flow and Temperature with Various Inlet Temperature (lpm/Celsius)
24.00
20.00
16.00
12.00
8.00
4.00
0.00
35
40
45
50
55
60
65
Hot water temperature (ºC)
Inlet (ºC) 4
Inlet (ºC) 10
Inlet (ºC) 16
Inlet (ºC) 21
Fig. 29 Flow/temperature charts
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Operation instructions
3.3 Use of remote control accessory
Fig. 33 Reset button
If the problem persists, contact your installer.
3.6 Program button
Fig. 30 Remote control
Program button can be used/programmed in the
appliance and in the remote control.
The wireless remote control accessory and the
temperature selector buttons on the front of the water
heater operate identically. Contact your distributor or
CEC to order if the remote control accessory is
preferred. Modification of the water heaters interior
control unit (Fig. 29, component 12) is required when
programming the remote control with this heater.
Programming “Program” function
Programming actions are similar for both controls
(appliance control pad and wireless remote control).
NOTE: up to 6 remote controls can be
programmed for one single water heater,
each with a range distance of 98 ft (30 m).
i
3.4 Operation
B When a hot water tap is opened, main burner ignites
Fig. 34 “Program” key
and LCD displays indication
.
B Press buttons
and
to select temperature to
be memorized.
B Hold “Program” button for 3 seconds to save
temperature.
When LCD stops blinking. Temperature is saved on
“Program”.
Fig. 31
B LCD blinks until selected temperature is reached.
Using “Program” function
In order to select memorized temperature
3.5 Reset button
B Press “Program” key.
If the LCD shows the error symbol
See the error code on LCD and consult
“Troubleshooting” section.
.
LCD shows pre-memorized temperature, which is now
the hot water selected temperature.
3.7 Locked condition
This condition is only valid for appliances with more
then 1 controller (appliances with remote control).
Fig. 35 Locked condition
Fig. 32
Whenever LCD shows
the temperature setting
After
following
instructions
indicated
in
cannot be adjusted because the appliance is in use by
a user which already selected a different temperature.
Appliance will be automatically unlocked after closing
hot water tap.
“Troubleshooting” section
B press reset button in order to make the appliance
ready-to-work.
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Maintenance and service
unit, the heater will communicate the source by these
error codes.
4
Maintenance and service
Warning: Always turn off the electrical
power supply, turn off the manual gas
valve and turn off the manual water
control valves whenever servicing.
BURNERS DO NOT IGNITE WHEN HOT WATER IS
TURNED ON
• Cold incoming water connection made to
wrong side of heater
Make sure cold water inlet connection is plumbed to
the right side of heater when facing unit
The unit should be checked once a year by a gas
technician. If repairs are needed, the repairs should be
done by a gas technician
• Water flow rate at hot water tap is too low
A minimum of 0.8 gallon/minute (3 l/m) is required to
activate the heater
To remove front cover
B Remove plastic decals on front panel (Page 5, Fig.
• Cold water inlet filter screen is dirty
Remove water inlet filter screen and clean. The
screen is located at the inlet connection to the water
heater, disconnecting the main cold supply line at the
heater is required. Check and clean faucet aerator
screens too.
4).
B Loosen the two Philips head screws located behind
decals.
B Lift front cover panel upward and remove.
Systems and parts that should be checked at
least once a year
• Crossover in plumbing
The heater activates when there is sufficient water
flow through its water valve, a minimum of 0.8 gallon/
minute (3 l/m) is required. If there is a crossover in the
plumbing, the necessary hot water flow rate through
the unit may not be reached, even though the flow at
the hot water tap is sufficient. A plumbing crossover
can be caused by a failed washer at a single lever
faucet, incorrect plumbing or a faulty mixing valve in
the piping. The crossover will create a back pressure
on the water heater and prevent an adequate flow of
water through it. To confirm there is no crossover in
the plumbing, shut off the cold water supply feed to
the water heater. Individually open each of the hot
water taps. There should be no water flowing under
a constant pressure. If there is a constant flow of
water then the plumbing crossover must be
corrected before the heater can operate properly.
Reference diagrams on pages 29 and 30.
• Venting system
• Burners -see page 29 for observation window
• Manual operation of the pressure relief valve to insure
correct operation
• Periodic cleaning of the water filter screen, see Fig.
24, chapter 2.13.
• Flushing the heat exchanger with a descaling
solution if mineral build up is evident. Scale build up
will shorten the life of the water heater, descale heat
exchanger thoroughly and repeat annually depending
on mineral content of ground water.
5
Troubleshooting
WATER IS TOO HOT
Introduction
• Temperature selection too high
The GWH-635-ES burner is activated by a water flow
valve. Numerous water related problems can cause this
water valve to malfunction such as: Insufficient water
flow volume to activate the burners at its minimum flow
requirement; Dirt in the water flow valve causing it to
malfunction; Sediment build-up in faucet aerators, or
shower heads; Uneven pressures between cold and hot
(with single lever mix valves); and Plumbing crossovers.
These water flow related problems can cause the
heater to deliver less than its full output, or to fail to
ignite or to shut down completely.
Problems stated below in upper case and in bold face
should be investigated when there is a problem with the
performance of the water heater but there is NO error
code on the heater's LCD display or wireless remote
control.
Lower temperature adjustment on heater or wireless
remote control accessory, see chapter 3.2.
WATER IS NOT HOT ENOUGH
• Temperature selection too low
Increase temperature adjustment on heater or
wireless remote control accessory, see chapter 3.2
• Btu input is too low due to inadequate gas line
sizing
See specifications in chapter 2.10 - 2.12. The
GWH-635-ES requires adequate gas pressure to
reach desired temperatures, to compensate for
inadequate gas supply or lack of gas pressure the
GWH-635-ES will effectively reach the selected
output temperature by reducing the hot water flow
rate. Its motorized water valve makes this adjustment
Any failures that result in a displayed error code are
referenced on page 26. A Functional Scheme of the
GWH-635-ES is detailed on page 28. If there is a
problem with the installation, venting or operation of the
• Cold water is mixing with the hot water outlet
(crossover)
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Troubleshooting
Test by following 4th bullet under BURNERS DO
NOT IGNITE WHEN HOT WATER IS TURNED ON.
control of the heater can be lowered to produce a
more comfortable hot water temperature.
• Inlet water pressure is erratic due to
fluctuating supply water pressure
LOW WATER FLOW/PRESSURE
• Too many hot water applications are being
used simultaneously or too much flow is being
demanded
For installation on a private well system with the use
of a pressure tank, the lowest pressure range setting
recommended is 30-50 psi (2.07-3.45 bar). The use
of a pressure reducing valve after the pressure tank
is also an effective way to maintain a constant water
pressure to the water heater. Watts brand 25AUB-
¾” or N35B-¾” pressure relief valves or equivalent
are suggested.
The GWH-635-ES will effectively support two 2.0-
2.5 gpm shower heads simultaneously or multiple
sink applications. Greater draws will result in
increased pressure drop and reduced flow at taps.
See flow/temperature chart on page 22.
• Btu input is too low due to inadequate gas line
sizing
NOISY BURNER / HEATER DURING OPERATION
See specifications in chapter 2.10 - 2.12. The
GWH-635-ES requires adequate gas pressure to
reach expected temperatures and flow rates, to
compensate for inadequate gas supply or lack of gas
pressure the GWH-635-ES will effectively reach the
selected output temperature, but only by reducing
the hot water flow rate. Its motorized water valve
makes this adjustment. Proper gas pressure will
need to be delivered before the motorized water
valve will allow greater flow rates through it. Lowering
the set temperature will also allow increased water
flow rate through the motorized water valve. See
flow/temperature chart on page 22.
• CO2 range is out of adjustment. The cover must be
in place to confirm CO2 readings. Operating with the
cover removed may cause a noisy or unstable burner.
See Chapter 9, CO2 adjustments can only be done
by a certified gas technician with a calibrated CO2
analyzer.
• Cold water inlet filter screen is dirty
Remove water inlet filter screen and clean. The
screen is located at the inlet connection to the water
heater, disconnecting the main cold supply line at the
heater is required. Check and clean faucet aerator
screens too.
HOT WATER TEMPERATURE FLUCTUATES /
UNIT DEACTIVATED
• Unbalanced pressure in water lines
Any restriction caused by the water heater in the hot
water system can result in uneven pressures
between the cold and the hot. In such cases when
mixing cold water at the tap (manually or
automatically through a mix-type shower valve) the
lower hot water pressure may be overpowered by the
higher cold water pressure in the building and cause
the hot water flow rate to fall below the minimum rate
required. A pressure balance valve will help to
resolve this symptom.
• Temperature balance valves
If the outlet water temperature is set too high, the
heater can produce temperatures that are too hot. A
temperature balance shower valve can automatically
mix in cold water to reduce such hot water
temperature. In the event of any temperature
instability with the use of a temperature balance
shower valve, refer to shower valve manufacturer's
instructions for internal adjustment setting.
Adjustments should be made to the hottest setting in
the shower valve. Additionally the temperature
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Troubleshooting
Display
Cause
Solution
E9
Temperature limiter opened circuit
(overheat). Trips at 220F (104C).
Check connections.*
Check heat exchanger condition.*
EA
No ionization during safety time (safety time
out).
Check gas pressure.*
Check that gas is not diluted with air, as a result
from recent gas pipeline rework.*.
Check if vent terminal is blocked (especially when
the appliance starts up for some seconds and then
looses ionization signal).*
Check ionization electrode.*
Check for a proper ground.*
FA
Leakage error (gas valves do not close gas
circuit).
Check gas valve and control unit.*
F7
E0
Ionization error (flame sensing at stand-by).
Internal software/hardware failure.
Check control unit.*
Check control unit.*
A7
Hot water temperature sensor/receiver
defect (from control unit).
Check water temperature sensor/receiver and
connections.*
Check room area temperature where heater is
located, it must be above 36°F (2°C)
A9
Hot water temperature sensor/receiver mis- Check that the water temperature sensor/receiver is
assembled (from control unit).
properly assembled in the water pipe.*
Check if vent terminal is blocked or if vent terminal is
according with chapter 2.9.*
In case of high altitude installation confirm that
necessary adjustment steps have been taken.*
C1
FAN rotation too low at start-up (from
control unit).
Check supply voltage.*
Check fan and connections.*
Check control unit.*
Check if vent terminal is blocked or if vent terminal is
according with chapter 2.9. *
Check CO2 levels (see chapter 9).*
C6
C7
FAN rotation too low at operation (from
control unit).
Check supply voltage.*
Check fan and connections.*
Check control unit.*
Check if vent terminal is according with
chapter 2.9.*
No rotational speed sensor signal from FAN Check fan and connections.*
Check control unit.*
Check CO2 levels (see chapter 9).*
CA
E2
Water flow signal over specified maximum
value
Check water valve and flow sensor.*
Inlet temperature sensor fault
Check water temperature sensor/receiver and
connections.*
Check room area temperature where heater is
located, it must be above 36°F (2°C)
A2
Overheat protection fault
Check connections to the overheat protection.*
Check sensor continuity.*
Check heat exchanger sealings and walls.*
Table 5
* By installer or service technician only.
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Electrical diagram
6
Electrical diagram
Fig. 36 Electrical scheme
1
2
3
4
5
6
Intlet water temperature sensor
Ionization sensor
Water flow sensor
Over heat protection
Temperature limiter
Gas valve
7
Fan
8
Water valve
9
AC Plug
10
11
12
13
14
15
16
17
Ignition electrode
Display PCB
ON/OFF switch
Fuse T 1,25A
Fuse T 3,15A
Terminal block
Ground post
Outlet water temperature sensor
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GWH-635-ES Functional scheme
7
GWH-635-ES Functional scheme
Fig. 37Functional scheme
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Interior components diagram and parts list
8
Interior components diagram and parts list
8.1 Interior components
Fig. 38 Components
1
Cover
2
3
4
5
6
7
8
On/Off switch
Reset button
LCD display
Program button
Temperature switches
Flue gas collector
Mixer
9
Heat exchanger
Observation window
Inlet air duct
Control unit
Exhaust fan
Water valve
10
11
12
13
14
15
Gas valve
Fig. 39 Appliance overview
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Interior components diagram and parts list
8.2 Components diagram
Fig. 40 Components Diagram
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Interior components diagram and parts list
8.3 Parts list
Item
Description
Reference
1
2
Front cover
8 705 421 837
8 705 506 661
8 705 406 285
8 704 701 052
8 716 102 607
8 704 701 054
8 700 205 147
8 700 400 015
8 710 103 045
8 714 606 002
8 705 700 097
8 700 507 001
8 700 205 134
8 708 505 016
8 708 120 515
8 704 701 050
8 708 107 020
8 707 204 039
8 705 700 115
8 704 701 059
8 704 701 062
8 707 021 019
8 700 103 014
8 707 207 153
8 707 207 133
8 704 401 220
8 704 401 214
8 704 401 239
8 704 401 221
8 700 400 019
8 705 504 114
8 705 504 115
8 705 700 100
8 705 700 114
8 700 715 156
8 700 715 155
8 700 507 069
8 700 715 247
8 707 206 204
Shield
3
Heat exchanger
Heat exchanger top gasket
Clip
4
5
6
Heat exchanger bottom gasket
O-ring
7
8
Temperature sensor
Washer 1/2"
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
Table 6
Wireform spring
Air inlet duct
Water filter
O-ring
Water valve with engine
Main burner
Fan / Burner gasket
Set of electrodes
Exhaust Fan
Gas / Air Mixer
Mixer / Fan gasket
Gas valve washer
Gas valve
Gas valve washer
Remote control
Control unit
Ignition cable
Cables / 24V
Cables
Power supply cord
Overheat cutoff fuse
Flue gas exhaust accessory
Combustion air inlet accessory
Flue gas collector
Flue gas collector collar
Cold water pipe
Hot water pipe
Air inlet screen
Crossover tube
Overheat sensor (ECO)
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Special adjustment for measuring and adjusting CO2 levels
9
Special adjustment for measuring and adjusting CO levels
2
The CO2 can only be adjusted by a certified gas
technician with a calibrated CO2 analyzer.
CO2 adjustment at minimum gas flow (P2) - See
table 7.
Factory
setting
Field settings
acceptable range
Caution: Converting the gas type can
only be done by a certified gas
technician with
analyzer. Call CEC for conversion
instructions.
a
calibrated CO2
Nat. Gas
9.00 %
Nat. Gas
max. input P1
min. input P2
8.00 % to 10.00 %
8.00 % to 10.00 %
LP Gas
9.00 %
LP Gas
10.80 %
10.80 %
Caution: Adjustments must only be
carried out by authorized service
personnel only.
max. input P1
min. input P2
10.00 % to 11.20 %
10.00 % to 11.20 %
* Final reading must be confirmed with the front cover
on, CO2 levels increase when the cover is installed.
Caution: The appliance should always
be disconnected from the power supply
before any maintenance is carried out.
Table 7
B Press “Program” key and turn ON/OFF switch to
position ON.
9.1 Adjusting the unit
Factory settings of this appliance are listed in table 7.
Further adjustment is only needed if optimal CO2 level
is required in order to assure the minimum possible
CO2 emissions. In this case a CO2 analyzer is required.
9.1.1 CO2 measuring port
B Loosen screw 1 (Fig. 41).
B Insert CO2 analyzer into measuring port (Fig. 41,
Fig. 42
pos. 1).
LCD shows “P2” and the appliance is ready to be
adjusted.
B Open hot water tap.
The appliance will run constantly at minimum power
output and minimum water flow. This program step can
also be used to measure minimum output and minimum
water flow.
B Turn the screw in order to regulate the air-gas mixture
inside the ventilator until the CO2 level required is
reached (Fig. 43, pos. 3).
CO2 adjustment at maximum gas flow (P1) - See
table 7.
Fig. 41
B Press
, until “P1” appears.
1
Measuring point
B Open hot water tap.
9.1.2 Selecting adjustment mode
The appliance will run constantly at maximum power
output and maximum water flow. This program step can
also be used to measure maximum output and maximum
water flow.
B ON/OFF switch in position OFF (0).
B Turn the screw in order to regulate the air-gas mixture
inside the ventilator until the CO2 level required is
reached (Fig. 43, pos. 3).
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Special adjustment for measuring and adjusting CO2 levels
NOTE:
decreases
turning
CO2
screw
level,
clockwise
turning
i
counterclockwise increases it.
Caution: Faulty ignition or noisy
operation may occur if CO2 levels are
adjusted outside the indicated range.
Fig. 43 Adjusting
Leave “Program” mode
B Turn ON/OFF switch in position OFF and then ON
again.
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Protecting the environment
10 Protecting the environment
Packing
The packing box may be fully recycled as confirmed by
the recycling symbol
.
Components
Many parts in the heater can be fully recycled in the end
of the product life. Contact your city authorities for
information about the disposal of recyclable products.
Saving water resources:
B Make sure you close all the taps after any use. Avoid
leaving the taps dripping. Repair any leaking tap.
B Whenever possible use taps with built-in water flow
limiters. They will give you the same comfort level
while saving water.
B Define the temperature you want, in the appliance or
with the remote control. This way you have the
precise water flow needed (mixing cold water to
regulate temperature will increase the water flow with
consequent waste of water).
For increased safety shut off the appliance from
the main water supply if your are staying away
from home for a considerable time.
At below freezing temperatures, disconnect the
plumbing connections to the heater and allow
the heater to drain.
To prevent any freeze damage, introduce short
bursts of compressed air (20-40 psi) through
these connections to remove the residual water
in the horizontal pipes and water valve.
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Fifteen Year Limited Warranty
11 Fifteen Year Limited Warranty
General
of the original water heater or a replaced water heater.
Certain service labor allowances are available to PHCC
member contractors, dependent on prior authorization
by CEC.
BOSCH PRO water heaters are warranted by the
Manufacturer (BOSCH) through Controlled Energy
Corp. Controlled Energy Corp. (CEC) will furnish a
replacement heat exchanger and will furnish a
replacement of any other part which fails in normal use
and service within the applicable periods specified
below, in accordance with the terms of this warranty.
The CEC replacement will be warranted for the
unexpired portion of the original warranty. This warranty
will be valid only for water heaters in possession of the
original purchaser as recorded on the warranty card.
NOTE: the water heater must be free of
damaging scale deposits and not subject
i
to gas pressures greater than those
shown on the rating plate, which must not
be altered, defaced or removed.
How to Make a Claim
Any claim for warranty parts should be made to your
local dealer, distributor or to CEC. If CEC, please
contact the Technical Support Department:
The Heat Exchanger
If the heat exchanger fails within fifteen (15) years after
the original installation and operation, CEC will furnish
a replacement heat exchanger. However, if the water
heater is installed in other than a single family dwelling,
this heat exchanger warranty is limited to two (2) years
from date of original installation and operation.
Controlled Energy Corp.
340 Mad River Park
Waitsfield, VT 05673
Phone: 866-330-2730
Exceptions
This warranty will not apply:
In most cases, the dealer or distributor will be able to
promptly honor your claim and subsequently notify
CEC. However, all replacements are made subject to
validation by CEC of in-warranty coverage. The
damaged or defective item must be made available in
exchange for the replacement.
• 1. to defects or malfunctions resulting from failure to
properly install, operate or maintain the unit in
accordance with the printed instructions provided;
• 2. to damage or abuse, accident, neglect or freezing
and other acts of nature;
• 3. to damage resulting from operation with either the
Miscellaneous
flame sensor rod or overheat sensor removed;
No one is authorized to make any other warranties on
behalf of CEC. It is expressly understood that the
replacement warranty of CEC shall be in lieu of any and
all other warranties, express or implied, including
warranties of merchantability or fitness for a particular
use or purpose, and further that CEC shall not be liable
for any loss or damage directly or indirectly arising from
the use of the hot water heater, or for any consequential
damages arising from such use (including damages
from water leakage). CEC’s sole liability with respect to
any defect shall be for the replacement of the defective
part(s). Some states do not allow such limitations and
exclusions, so the above may not apply to you.
• 4. to failure of the heat exchanger resulting from the
operation of the water heater in a corrosive
atmosphere or at water temperatures exceeding the
maximum rating, or if the water heater is not supplied
with potable water;
• 5. to defects or damage cause by any attachment
or modification, including any energy-saving device.
All Other Parts
If any other part fails within three (3) years after original
installation and operation, CEC will furnish a
replacement part free of charge.
This warranty gives specific legal rights. You may also
have other rights which vary from state to state.
Shipping costs
In addition to supplying the replacement part(s), CEC
will provide ground service delivery for these parts.
Expedited or upgraded shipping will be charged to the
customer.
Service Labor Costs
This warranty does not cover any labor costs
associated with service, removal or re-installation of
part(s). All such costs must be borne by the Purchaser.
Additionally, this warranty does not cover any labor
costs associated with service, removal or re-installation
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Replacement Parts available from North American Distributor
CONTROLLED ENERGY CORP.
340 Mad River Park
Waitsfield, Vermont 05673
Phone 866-330-2730
Fax (802) 496-6924
VULCANO Termodomésticos S.A.
Estrada de Cacia
3801 - 856 Aveiro - PORTUGAL
Recycled paper
© 2004 Controlled Energy Corporation,
Waitsfield, VT all rights reserved
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