INSTALLATION
INSTRUCTIONS
SL280DFV
E 2011 Lennox Industries Inc.
Dallas, Texas, USA
®
DAVE LENNOX SIGNATURE
COLLECTION GAS FURNACE
DOWNFLOW AIR DISCHARGE
506710−01
06/2011
Supersedes 01/2011
Litho U.S.A.
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person-
al injury or loss of life. Installation and service must
be performed by a licensed professional installer (or
equivalent), service agency or the gas supplier.
DOWNFLOW
AIR FLOW
NOTICE
A thermostat is not included and must be ordered
separately.
D The Lennox icomfort Toucht thermostat must be
used in communicating applications.
D In non−communicating applications, the Lennox
®
CAUTION
As with any mechanical equipment, personal injury
can result from contact with sharp sheet metal
edges. Be careful when you handle this equipment.
ComfortSense 7000 thermostat may be used, as
well as other non−communicating thermostats.
In all cases, setup is critical to ensure proper sys-
tem operation.
Field wiring for both communicating and non−com-
municating applications is illustrated in diagrams,
This is a safety alert symbol and should never be ignored.
When you see this symbol on labels or in manuals, be alert
to the potential for personal injury or death.
Table of Contents
Unit Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Parts Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SL280DFV Gas Furnace . . . . . . . . . . . . . . . . . . . . . . . . . 4
Shipping and Packing List . . . . . . . . . . . . . . . . . . . . . . . . 4
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Use of Furnace as a Construction Heater . . . . . . . . . . . 5
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Combustion, Dilution & Ventilation Air . . . . . . . . . . . . . . 6
Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Integrated Control Settings . . . . . . . . . . . . . . . . . . . . . . . 32
Blower Performance Data . . . . . . . . . . . . . . . . . . . . . . . . 35
Unit Start−Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Gas Pressure Adjustment . . . . . . . . . . . . . . . . . . . . . . . . 40
Proper Combustion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
High Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Other Unit Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Heating Sequence of Operation . . . . . . . . . . . . . . . . . . . 42
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Planned Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Repair Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Integrated Control Diagnostic Codes . . . . . . . . . . . . . . . 48
Program Unit Capacity/Size Mode . . . . . . . . . . . . . . . . . 55
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Setting Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Duct System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
506710−01
06/11
Page 1
*P506710-01*
*2P0611*
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Parts Arrangement
BLOWER ASSEMBLY
SECONDARY LIMIT
GASKET
FLUE CHASE
CONTROL BOX
(Includes two−stage integrated control,
transformer and circuit breaker)
INTERNAL FLUE
PIPE ASSEMBLY
DOOR INTERLOCK SWITCH
ROLLOUT SWITCH
PRIMARY LIMIT LOCATION
HEAT EXCHANGER
COMBUSTION AIR INDUCER
PRESSURE SWITCHES
COMBUSTION AIR INDUCER
GAS VALVE
INNER BLOWER ACCESS PANEL
BURNER BOX ASSEMBLY
ACCESS PANEL
FIGURE 1
Page 3
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SL280DFV Gas Furnace
CAUTION
As with any mechanical equipment, personal injury
can result from contact with sharp sheet metal
edges. Be careful when you handle this equipment.
The SL280DFV gas furnace is equipped with a two−stage,
variable speed integrated control. the control is compat-
ible with:
®
Communicating thermostats − icomfort Touch .
Certifications
Non−communicating thermostats − ComfortSense or oth-
er conventional thermostats.
SL280DFV units are CSA International certified.
In the USA, installation of gas furnaces must conform with
local building codes. In the absence of local codes, units
must be installed according to the current National Fuel
Gas Code (ANSI-Z223.1). The National Fuel Gas Code is
available from the following address:
Control systems − Harmony IIIꢀ Zone Control System
(non−communicating). Each SL280DFV unit is shipped
ready for installation in the downflow position.
American National Standards Institute, Inc.
11 West 42nd Street
Shipping and Packing List
New York, NY 10036
Package 1 of 1 contains
1 − Assembled SL280DFV unit
1 − Bag assembly containing the following:
2 −Screws
Clearances
Adequate clearance must be made around the air open-
ings into the vestibule area. In order to ensure proper unit
operation, combustion and ventilation air supply must be
provided according to the current National Fuel Gas Code.
1 −Snap bushing
1 −Snap plug
Vent installations must be consistent with the venting
tables (in this instruction) and applicable provisions of local
building codes.
1 − Wire tie
1 −Vent warning label
1 −Owner’s manual and warranty card
This furnace is CSA International certified for installation
clearances to combustible material as listed on the unit
service clearances must take precedence over fire protection
clearances.
The following items may be ordered separately:
1 − Thermostat
1 − Propane/LP changeover kit
1 − Combustible flooring base
Installed Locations
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
For installation in a residential garage, the furnace must
be installed so that the burner(s) and the ignition source
are located no less than 18 inches (457 mm) above the
floor. The furnace must be located or protected to avoid
physical damage by vehicles. When a furnace is installed
in apublic garage, hangar, or other building that has a haz-
ardous atmosphere, the furnace must be installed accord-
ing to recommended good practice requirements and cur-
rent National Fuel Gas Code.
Safety Information
DANGER
Danger of explosion.
There are circumstances in which odorant used with
LP/propane gas can lose its scent. In case of a leak,
LP/propane gas will settle close to the floor and may
be difficult to smell. An LP/propane leak detector
should be installed in all LP applications.
NOTE − Furnace must be adjusted to obtain a temperature
rise (high and low fire) within the range(s) specified on the unit
nameplate. Failure to do so may cause erratic limit operation
and may also result in premature heat exchanger failure.
This SL280DFV furnace must be installed so that its electri-
cal components are protected from water.
Installed in Combination with a Cooling Coil
WARNING
When this furnace is used with cooling units, it shall be
installed in parallel with, or on the upstream side of, cooling
units to avoid condensation in the heating compartment.
With a parallel flow arrangement, a damper (or other
means to control the flow of air) must adequately prevent
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person-
al injury or loss of life. Installation and service must
be performed by a licensed professional installer (or
equivalent), service agency or the gas supplier.
Page 4
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damper is manually operated, it must be equipped to pre-
vent operation of either the heating or the cooling unit, un-
less it is in the full HEAT or COOL setting.
SL280DFV units may be used for heating of buildings or
structures under construction, if the following conditions
are met:
D The vent system must be permanently installed per
these installation instructions.
D A room thermostat must control the furnace. The use of
fixed jumpers that will provide continuous heating is not
allowed.
D The return air duct must be provided and sealed to the
furnace.
AIR HANDLER
GAS UNIT
D Return air temperature range between 60°F (16°C) and
80°F (27°C) must be maintained.
D Air filters must be installed in the system and must be
maintained during construction.
Dampers
D Air filters must be replaced upon construction comple-
tion.
Dampers
(open during cooling
(open during heating
operation only)
operation only)
D The input rate and temperature rise must be set per the
furnace rating plate.
D One hundred percent (100%) outdoor air must be pro-
vided for combustion air requirements during construc-
tion. Temporary ducting may supply outdoor air to the
furnace. Do not connect duct directly to the furnace.
Size the temporary duct following these instructions in
section for Combustion, Dilution and Ventilation Air in a
confined space with air from outside.
FIGURE 1
When installed, this furnace must be electrically grounded
according to local codes. In addition, in the United States,
installation must conform with the current National Elec-
tric Code, ANSI/NFPA No. 70. The National Electric Code
(ANSI/NFPA No. 70) is available from the following ad-
dress:
D The furnace heat exchanger, components, duct system,
air filters and evaporator coils must be thoroughly
cleaned following final construction clean−up.
D All furnace operating conditions (including ignition, in-
put rate, temperature rise and venting) must be verified
according to these installation instructions.
National Fire Protection Association
1 Battery March Park
General
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
Quincy, MA 02269
NOTE − This furnace is designed for a minimum continu-
ous return air temperature of 60°F (16°C) or an intermit-
tent operation down to 55°F (13°C) dry bulb for cases
where a night setback thermostat is used. Return air tem-
perature must not exceed 85°F (29°C) dry bulb.
In addition to the requirements outlined previously, the fol-
lowing general recommendations must be considered
when installing a SL280DFV furnace:
D Place the furnace as close to the center of the air dis-
tribution system as possible. The furnace should also be
located close to the chimney or vent termination point.
The SL280DFV furnace may be installed in alcoves, clos-
ets, attics, basements, garages, and utility rooms in the
downflow position.
D Do not install the furnace where drafts might blow direct-
ly into it. This could cause improper combustion and un-
safe operation.
This furnace design has not been CSA International certi-
fied for installation in mobile homes, recreational vehicles,
or outdoors.
D Do not block the furnace combustion air openings with
clothing, boxes, doors, etc. Air is needed for proper
combustion and safe unit operation.
Use of Furnace as Construction Heater
D When the furnace is installed in an attic or other insu-
lated space, keep insulation away from the furnace.
Lennox does not recommend the use of SL280DFV units
as a construction heater during any phase of construction.
Very low return air temperatures, harmful vapors and op-
eration of the unit with clogged or misplaced filters will dam-
age the unit.
NOTE − The Commonwealth of Massachusetts stipu-
lates these additional requirements:
D Gas furnaces shall be installed by a licensed plumb-
er or fitter only.
Page 5
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D The gas cock must be ꢀT handle" type.
CAUTION
D When a furnace is installed in an attic, the passage-
way to and service area surrounding the equipment
shall be floored.
Insufficient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also cause
excess water in the heat exchanger resulting in rust-
ing and premature heat exchanger failure. Excessive
exposure to contaminated combustion air will result
in safety and performance related problems. Avoid
exposure to the following substances in the combus-
tion air supply:
WARNING
Product contains fiberglass wool.
Disturbing the insulation in this product during
installation, maintenance, or repair will expose you
to fiberglass wool. Breathing this may cause lung
cancer. (Fiberglass wool is known to the State of Cal-
ifornia to cause cancer.)
Permanent wave solutions
Chlorinated waxes and cleaners
Chlorine base swimming pool chemicals
Water softening chemicals
De-icing salts or chemicals
Carbon tetrachloride
Halogen type refrigerants
Fiberglass wool may also cause respiratory, skin,
and eye irritation.
Cleaning solvents (such as perchloroethylene)
Printing inks, paint removers, varnishes, etc.
Hydrochloric acid
Cements and glues
Antistatic fabric softeners for clothes dryers
Masonry acid washing materials
To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown below, or contact your
supervisor.
Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379−9900
All gas-fired appliances require air for the combustion pro-
cess. If sufficient combustion air is not available, the fur-
nace or other appliances will operate inefficiently and un-
safely. Enough air must be provided to meet the needs of all
fuel-burning appliances and appliances such as exhaust
fans which force air out of the house. When fireplaces, ex-
haust fans, or clothes dryers are used at the same time as
the furnace, much more air is necessary to ensure proper
combustion and to prevent a downdraft. Insufficient air
causes incomplete combustion which can result in carbon
monoxide.
Combustion, Dilution & Ventilation Air
In the past, there was no problem in bringing in sufficient out-
door air for combustion. Infiltration provided all the air that
was needed. In today’s homes, tight construction practices
make it necessary to bring in air from outside for combus-
tion. Take into account that exhaust fans, appliance vents,
chimneys, and fireplaces force additional air that could be
used for combustion out of the house. Unless outside air is
brought into the house for combustion, negative pressure
(outside pressure is greater than inside pressure) will build
to the point that a downdraft can occur in the furnace vent
pipe or chimney. As a result, combustion gases enter the liv-
ing space creating a potentially dangerous situation.
In addition to providing combustion air, fresh outdoor air
dilutes contaminants in the indoor air. These contami-
nants may include bleaches, adhesives, detergents, sol-
vents and other contaminants which can corrode furnace
components.
The requirements for providing air for combustion and ven-
tilation depend largely on whether the furnace is installed in
an unconfined or a confined space.
In the absence of local codes concerning air for combus-
tion and ventilation, use the guidelines and procedures in
this section to install SL280DFV furnaces to ensure effi-
cient and safe operation. You must consider combustion air
needs and requirements for exhaust vents. A portion of this
information has been reprinted with permission from the
National Fuel Gas Code (ANSI-Z223.1). This reprinted ma-
terial is not the complete and official position of the ANSI on
the referenced subject, which is represented only by the
standard in its entirety.
Unconfined Space
An unconfined space is an area such as a basement or
large equipment room with a volume greater than 50 cubic
3
feet (1.42 m ) per 1,000 Btu (.29 kW) per hour of the com-
bined input rating of all appliances installed in that space.
This space also includes adjacent rooms which are not
separated by a door. Though an area may appear to be un-
confined, it might be necessary to bring in outdoor air for
combustion if the structure does not provide enough air by
infiltration. If the furnace is located in a building of tight
construction with weather stripping and caulking around
the windows and doors, follow the procedures in the air
from outside section.
CAUTION
Do not install the furnace in a corrosive or contami-
nated atmosphere. Meet all combustion and ventila-
tion air requirements, as well as all local codes.
Page 6
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Confined Space
Air from Inside
If the confined space that houses the furnace adjoins a
space categorized as unconfined, air can be brought in by
providing two permanent openings between the two
spaces. Each opening must have a minimum free area of 1
A confined space is an area with a volume less than 50 cu-
3
bic feet (1.42 m ) per 1,000 Btu (.29 kW) per hour of the
combined input rating of all appliances installed in that
space. This definition includes furnace closets or small
equipment rooms.
2
square inch (645 mm ) per 1,000 Btu (.29 kW) per hour of
total input rating of all gas−fired equipment in the confined
space. Each opening must be at least 100 square inches
When the furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside the space contain-
ing the furnace, the return air must be handled by ducts
which are sealed to the furnace casing and which terminate
outside the space containing the furnace. This is especially
important when the furnace is mounted on a platform in a
confined space such as a closet or small equipment room.
Even a small leak around the base of the unit at the platform
or at the return air duct connection can cause a potentially
dangerous negative pressure condition. Air for combustion
and ventilation can be brought into the confined space either
from inside the building or from outside.
2
(64516 mm ). One opening shall be within 12 inches (305
mm) of the top of the enclosure and one opening within 12
Air from Outside
If air from outside is brought in for combustion and ventila-
tion, the confined space must have two permanent open-
ings. One opening shall be within 12 inches (305 mm) of the
top of the enclosure and one opening within 12 inches (305
mm) of the bottom. These openings must communicate di-
rectly or by ducts with the outdoors or spaces (crawl or at-
tic) that freely communicate with the outdoors or indirectly
through vertical ducts. Each opening shall have a minimum
2
EQUIPMENT IN CONFINED
SPACE ALL AIR FROM INSIDE
free area of 1 square inch (645 mm ) per 4,000 Btu (1.17
CHIMNEY
OR GAS
VENT
kW) per hour of total input rating of all equipment in the en-
the outdoors through horizontal ducts, each opening shall
2
have a minimum free area of 1 square inch (645 mm ) per
2,000 Btu (.56 kW) per total input rating of all equipment in
the enclosure. See figure 5.
WATER
HEATER
FURNACE
When ducts are used, they shall be of the same cross−sec-
tional area as the free area of the openings to which they
connect. The minimum dimension of rectangular air ducts
shall be no less than 3 inches (75 mm). In calculating free
area, the blocking effect of louvers, grilles, or screens must
be considered. If the design and free area of protective cov-
ering is not known for calculating the size opening required,
it may be assumed that wood louvers will have 20 to 25 per-
cent free area and metal louvers and grilles will have 60 to
75 percent free area. Louvers and grilles must be fixed in the
open position or interlocked with the equipment so that they
are opened automatically during equipment operation.
OPENINGS
(To Adjacent
Room)
NOTE − Each opening shall have a free area of at least one square
2
inch (645 mm ) per 1,000 Btu (.29 kW) per hour of the total input rat-
ing of all equipment in the enclosure, but not less than 100 square
2
inches (64516 mm ).
FIGURE 2
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EQUIPMENT IN CONFINED SPACE
ALL AIR FROM OUTSIDE
(Inlet Air from Crawlspace and Outlet Air to Ventilated Attic)
CHIMNEY OR
GAS VENT
VENTILATION LOUVERS
(Each end of attic)
OUTLET
AIR
WATER
HEATER
FURNACE
INLET
AIR
VENTILATION
LOUVERS
(For unheated crawl space)
NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch (645
2
mm ) per 4,000 Btu (1.17 kW) per hour of the total input rating of all equipment in the enclosure.
FIGURE 3
EQUIPMENT IN
CONFINED SPACE
ALL AIR FROM
OUTSIDE
EQUIPMENT IN CONFINED SPACE
ALL AIR FROM OUTSIDE
(All Air Through Ventilated Attic)
CHIMNEY
OR GAS
VENT
CHIMNEY
OR GAS
VENT
WATER
HEATER
VENTILATION LOUVERS
(Each end of attic)
OUTLET AIR
OUTLET
AIR
FURNACE
FURNACE
INLET AIR
(Ends 12 in.
above bottom)
INLET AIR
WATER
HEATER
NOTE − Each air duct opening shall have a free area of at least
2
one square inch (645 mm ) per 2,000 Btu (.59 kW) per hour of
the total input rating of all equipment in the enclosure. If the
equipment room is located against an outside wall and the air
openings communicate directly with the outdoors, each open-
ing shall have a free area of at least one square inch (645 mm )
per 4,000 Btu (1.17 kW) per hour of the total input rating of all
other equipment in the enclosure.
NOTE−The inlet and outlet air openings shall each have a
2
free area of at least one square inch (645 mm ) per 4,000
Btu (1.17 kW) per hour of the total input rating of all equip-
ment in the enclosure.
2
FIGURE 4
FIGURE 5
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Downflow Installation
CAUTION
Downflow unit installs in three ways: on non−combustible
flooring, on combustible flooring using a downflow com-
bustible flooring base, or on a reverse−flow cooling cabinet.
Do not drag the unit across the floor.
The furnace and downflow combustible flooring
base shall not be installed directly on carpeting, tile,
or other combustible material other than wood floor-
ing.
1 − Cut floor opening keeping in mind clearances listed on
unit rating plate. Also keep in mind gas supply connec-
tions, electrical supply, flue and air intake connections
and sufficient installation and servicing clearances.
See table 1 for correct floor opening size.
2 − Flange warm air plenum and lower the plenum into the
opening.
SL280DFV UNIT
SUPPLY AIR PLENUM
DOWNFLOW
PROPERLY
COMBUSTIBLE
SIZED FLOOR
FLOORING BASE
OPENING
3 − Set the unit over the plenum and seal the plenum to
the unit.
4 − Ensure that the seal is adequate.
FIGURE 7
SL280DFV UNIT
COMBUSTIBLE FLOOR OPENING SIZE
Front to Rear
Side to Side
Cabinet Width
in.
mm
in.
mm
SUPPLY AIR
PLENUM
22
22
22
559
559
559
15−3/4
18−3/4
22−3/4
400
476
578
A (14.5")
B (17.5")
C (21")
OPENING
NOTE − Floor opening dimensions listed are 1/4 inch (6 mm) larger than
unit opening. See unit dimensions on page 2.
2 − After opening is cut, set combustible flooring base into
opening.
FIGURE 6
TABLE 1
3 − Check sealing strips on combustible flooring base to
make sure they are properly glued and positioned.
4 − Lower supply air plenum into downflow combustible
flooring base until plenum flanges seal against the
strips.
NON−COMBUSTIBLE FLOOR OPENING SIZE
Front to Rear
Side to Side
NOTE − Be careful not to damage sealing strips. Check
for a tight seal.
Cabinet Width
in.
mm
in.
mm
A (14.5")
B (17.5")
C (21")
19−3/4
19−3/4
19−3/4
502
502
502
13−1/4
16−1/4
19−3/4
337
413
502
5 − Set the furnace over the plenum.
6 − Ensure that the seal between the furnace and plenum
is adequate.
NOTE − Door opening dimensions listed are 1/4 inch (6 mm) larger than
the unit opening. See unit dimensions on page 2.
1 − Refer to reverse−flow coil installation instructions for
correctly sized opening in floor and installation of cabi-
net.
1 − When unit is installed on a combustible floor, a down-
flow combustible flooring base must be installed be-
tween the furnace and the floor. The base must be or-
dered separately.
NOTE − Downflow combustible flooring kit is not used
2 − When cooling cabinet is in place, set and secure the
furnace according to the instructions that are provided
with the cooling coil. Secure the furnace to the cabinet.
See table 2 for opening size to cut in floor.
3 − Seal the cabinet and check for air leaks.
Page 9
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Setting Equipment
SL280DFV UNIT
WARNING
Do not install the furnace on its front, back or in the
return air ducts to the back of the furnace. Doing so
will adversely affect the operation of the safety con-
trol devices, which could result in personal injury or
death.
COOLING COIL
PLENUM
PROPERLY
SIZED FLOOR
OPENING
Install the SL280DFV gas furnace as shipped in the
downflow position only. Do not install the furnace hori-
zontally.
Select a location that allows for the required clearances
that are listed on the unit nameplate. Also consider gas
supply connections, electrical supply, vent connection,
and installation and service clearances [24 inches (610
mm) at unit front]. The unit must be level.
FIGURE 8
Return Air Opening −− Downflow Units
The following steps should be taken when installing ple-
num:
1 − Bottom edge of plenum should be flanged with a
NOTE − Units with 1/2 hp blower motors are equipped with
leg is equipped with a shipping bolt and a flat white plastic
washer (rather than the rubber mounting grommet used
with a flexible mounting leg). The bolt and washer must
be removed before the furnace is placed into opera-
tion. After the bolt and washer have been removed, the rig-
id leg will not touch the blower housing.
PLENUM
SECURE FROM
OUTSIDE CABINET
Side View
HEMMED EDGE
SEALING STRIP
(Field Provided)
CABINET SIDE PANEL
SL280DFV07036A WITH 1/2 HP
BLOWER MOTOR
FIGURE 9
2 − Sealing strip should be used.
3 − In all cases, plenum should be secured to top flanges
of furnace with sheet metal screws.
RIGID LEG
remove shipping bolt and washer
PLENUM
SECURE FROM IN-
Side View
SIDE CABINET
HEMMED EDGE
FIGURE 11
FIBERGLASS
SEALING STRIP
CABINET SIDE
(Field Provided)
PANEL
FIGURE 10
WARNING
4 − In closet installations, it may be impossible to install
sheet metal screws from the outside. In this case,
make plenum with a removable front and install
The blower access panel must be securely in place
when the blower and burners are operating. Gas
fumes, which could contain carbon monoxide, can
be drawn into living space resulting in personal inju-
ry or death.
5 − Make certain that an adequate seal is made.
Page 10
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Horizontal
Front
Back
FIGURE 12
Downflow Application
Allow for clearances to combustible materials as indi-
cated on the unit nameplate. Minimum clearances for
WARNING
Improper installation of the furnace can result in per-
sonal injury or death. Combustion and flue products
must never be allowed to enter the return air system
or the living space. Use screws and joint tape to seal
the return air system to the furnace.
Downflow Application Installation Clearances
Top
In platform installations with bottom return air, the
furnace should be sealed airtight to the return air ple-
num. A door must never be used as a portion of the
return air duct system. The base must provide a
stable support and an airtight seal to the furnace. Al-
low absolutely no sagging, cracks, gaps, etc.
The return and supply air duct systems must never
be connected to or from other heating devices such
as a fireplace or stove, etc. Fire, explosion, carbon
monoxide poisoning, personal injury and/or proper-
ty damage could result.
Left Side
Right Side
Bottom
Type C
Type of Vent
Connector
Filters
Type B1
This unit is not equipped with a filter or rack. A field−pro-
vided high−velocity filter is required for the unit to operate
Top
*Front
Back
Sides
Vent
1 in. (25 mm)
1 in. (25 mm)
2−1/4 in. (57 mm)**
2−1/4in. (57 mm)
A filter must be in place any time the unit is operating.
0
0†
0
0
TABLE 3
Cabinet Width
Return Air Filter Size (inches)
6 in. (152 mm)
NC††
1 in. (25 mm)
NC††
A (14−1/2")
B (17−1/2")
C (21")
14 x 25 x 1 (1)
16 x 25 x 1 (1)
20 x 25 x 1 (1)
Floor
*Front clearance in alcove installation must be 24 in. (610 mm).
Maintain a minimum of 24 in. (610 mm) for front service access.
** 3−1/4 in. if single wall vent pipe is used.
†Left side requires 3 in. if a single wall vent is used on 14 −1/2 in. cab-
inets, or 2 in. if a single wall vent is used on 17 − 1/2 in. cabinets.
††The furnace may be installed on a combustible wood floor if an
optional additive base is installed between the furnace and the
combustible floor.
FIGURE 13
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Refer to the tables and the venting information contained in
these instructions to properly size and install the venting
system.
Duct System
Use industry-approved standards (such as those pub-
lished by Air Conditioning Contractors of America or Ameri-
can Society of Heating, Refrigerating and Air Conditioning
Engineers) to size and install the supply and return air duct
system. This will result in a quiet and low-static system that
has uniform air distribution.
IMPORTANT
Once the venting system is installed, attach the ꢀDis-
connected Vent" warning sticker to a visible area of
the plenum near the vent pipe. The warning sticker
is provided in the bag assembly. Order kit 66W04 for
additional stickers.
NOTE − Do not operate the furnace in the heating mode
with an external static pressure that exceeds 0.8 inches
w.c. Higher external static pressures may cause erratic lim-
it operation.
Ensure that you have made a seal between the supply air
plenum and the furnace and between the furnace and the
return air plenum.
WARNING
Asphyxiation hazard. The exhaust vent for this fur-
nace must be securely connected to the furnace flue
transition at all times.
Return Air Plenum
Return air must not be drawn from a room where this
furnace, or any other gas−fueled appliance (i.e., water
heater), or carbon monoxide−producing device (i.e.,
wood fireplace) is installed. When return air is drawn
from aroom, a negative pressure is created in the room. If
a gas appliance is operating in a room with negative pres-
sure, the flue products can be pulled back down the vent
pipe and into the room. This reverse flow of the flue gas
may result in incomplete combustion and the formation
of carbon monoxide gas. This toxic gas might then be dis-
tributed throughout the house by the furnace duct sys-
tem.
VENT CONNECTION
“DISCONNECTED VENT”
WARNING
STICKER
FLUE TRANSITION
COLLAR
Venting
A 4−inch diameter flue transition is factory-installed on all
models. Modifying or removing the flue transition will
cause the unit to operate unsafely and will void the unit
certification. The vent connector does not require insula-
tion.
FIGURE 14
Use self−drilling sheet metal screws or a mechanical fas-
tener to firmly secure the vent pipe to the round collar of the
flue transition. If self−drilling screws are used to attach the
vent pipe, it is recommended that three be used. Drive one
self−drilling screw through the front and one through each
side of the vent pipe and collar. See figure 14.
The SL280DFV series units are classified as fan−assisted
Category I furnaces when vertically vented according to
the latest edition of National Fuel Gas Code (NFPA 54 /
ANSI Z223.1). A fan−assisted Category I furnace is an ap-
pliance equipped with an integral mechanical means to ei-
ther draw or force combustion products through the com-
bustion chamber and/or heat exchanger.
Masonry chimneys used to vent Category I central fur-
naces must be either tile-lined or lined with a listed metal
lining system or dedicated gas vent. Unlined masonry
mon venting.
NOTE − Use these instructions as a guide. They do not su-
persede local codes. This furnace must be vented accord-
ing to all local codes, these installation instructions, and the
provided venting tables in these instructions
The venting tables in this manual were extracted from the
National Fuel Gas Code (NFPA 54 / ANSI Z223.1) and are
provided as a guide for proper vent installation. Proper ap-
plication, termination, construction and location of vents
must conform to local codes having jurisdiction. In the ab-
sence of local codes, the NFGC serves as the defining doc-
ument.
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Common Venting Using Tile−Lined Interior Masonry Chimney and Combined Vent Connector
MINIMUM LENGTH = AS SHORT AS PRACTICAL.
FOR MAXIMUM LENGTH SEE NOTE TO LEFT
INTERIOR TILE−LINED
MASONRY CHIMNEY
NOTE− Refer to provided venting
tables for installations.
NOTE − the chimney must be properly
sized per provided venting tables or
lined with listed metal lining system.
VENT
CONNECTOR
OTHER
APPLIANCE
PERMANENTLY
SEALED FIREPLACE
OPENING
FURNACE
FIGURE 15
Venting Using a Masonry Chimney
DO NOT insulate the space between the liner and the
chimney wall with puffed mica or any other loose gran-
ular insulating material
The following additional requirements apply when a lined
masonry chimney is used to vent this furnace.
A chimney with one or more sides exposed to the outside of
the structure is considered to be an exterior chimney.
IMPORTANT
An exterior masonry chimney that is not tile−lined must be
lined with B1 vent or a listed insulated flexible metal vent.
An exterior tile−lined chimney that is sealed and capped
may be lined with a listed uninsulated flexible metal vent.
SINGLE appliance venting of a fan-assisted furnace
into a tile-lined masonry chimney (interior or outside
wall) is PROHIBITED. The chimney must first be lined
with either type B1 vent or an insulated single wall
flexible vent lining system which has been sized ac-
cording to the provided venting tables and the vent
pipe manufacturer’s instructions.
If the existing chimney will not accommodate a listed metal
liner, either the chimney must be rebuilt to accommodate
one of these liners or an alternate approved venting meth-
od must be found.
A fan−assisted furnace may be commonly vented into an
existing lined masonry chimney if the following conditions
are met:
Insulation for the flexible vent pipe must be an encapsu-
lated fiberglass sleeve recommended by the flexible vent
pipe manufacturer. See figure 16.
S The chimney is currently serving at least one drafthood
equipped appliance
Common Venting Using Metal−Lined Masonry Chimney
S The vent connectors and chimney are sized according
to the provided venting tables.
SEALED
MAX. LENGTH
−− SEE NOTE
BELOW.
If type B1 double-wall vent is used inside a chimney, no oth-
er appliance can be vented into the chimney. The outer wall
of type B1 vent pipe must not be exposed to flue products.
5 ft. (1.5 m)
minimum
MIN. LENGTH −− AS
SHORT AS PRACTICAL
EXTERIOR
CHIMNEY WITH
METAL
A type B1 vent or masonry chimney liner shall terminate
above the roof surface with a listed cap or a listed roof as-
sembly according to the terms of their respective listings
and the vent manufacturer’s instructions.
LINER
VENT CONNECTOR
4 in. (102 mm)
minimum
FURNACE
When inspection reveals that an existing chimney is not
safe for the intended purpose, it shall be rebuilt to conform
to nationally recognized standards, lined or relined with
suitable materials, or replaced with a gas vent or chimney
suitable for venting SL280DFV series units. The chimney
passageway must be checked periodically to ensure that it
is clear and free of obstructions.
OTHER
APPLIANCE
PERMANENTLY
SEALED FIREPLACE
OPENING
NOTE 1 − Refer to the provided venting tables for installations.
Do not install a manual damper, barometric draft regulator,
or flue restrictor between the furnace and the chimney.
FIGURE 16
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Never connect a Category I appliance to a chimney that is
servicing a solid−fuel appliance. If a fireplace chimney flue
is used to vent this appliance, the fireplace opening must
be permanently sealed.
TABLE 4
Maximum Horizontal
Connector Length feet (m)
Connector Diameter
inches (mm)
3 (76)
4 (102)
5 (127)
6 (152)
7 (178)
4−1/2 (1.37)
6 (1.83)
A type B or listed chimney lining system that passes
through an unused masonry chimney flue is not considered
to be exposed to the outdoors.
7−1/2 (2.29)
9 (2.74)
General Venting Requirements
10−1/2 (3.20)
Vent all SL280DFV furnaces according to these instruc-
tions:
9 − If the common vertical vent is offset, the maximum
common vent capacity listed in the common venting
tables should be reduced by 20%, the equivalent of two
90° elbows (0.80 x maximum common vent capacity).
The horizontal length of the offset shall not exceed
1-1/2 feet (.46 m) for each inch (25 mm) of common
vent diameter.
1 − Vent diameter recommendations and maximum allow-
able piping runs are found in the provided venting
tables.
2 − In no case should the vent or vent connector diameter
be less than the diameter specified in the provided
venting tables.
10 − The vent pipe should be as short as possible with the
least number of elbows and angles required to com-
plete the job. Route the vent connector to the vent us-
ing the shortest possible route.
3 − The minimum vent capacity determined by the sizing
tables must be less than the low fire input rating and the
maximum vent capacity must be greater than the high
fire input rating.
11 − A vent connector shall be supported without any dips
or sags and shall slope a minimum of 1/4 inch (6.4 mm)
per linear foot (305 mm) of connector, back toward the
appliance.
4 − Single appliance vents − If the vertical vent or tile-lined
chimney has a larger diameter or flow area than the
vent connector, use the vertical vent diameter to de-
termine the minimum vent capacity and the vent
connector diameter to determine the maximum vent
capacity. The flow area of the vertical vent, however,
shall not exceed 7 times the flow area of the listed ap-
pliance categorized vent area, drafthood outlet area or
flue collar area unless designed according to approved
engineering methods.
12 − Vent connectors shall be firmly attached to the furnace
flue collar by self−drilling screws or other approved
means, except vent connectors of listed type B vent
material which shall be assembled according to the
manufacturer’s instructions. Joints between sections
of single wall connector piping shall be fastened by
screws or other approved means.
13 − When the vent connector used for Category I ap-
pliances must be located in or pass through a crawl-
space or other areas which may be cold, that portion of
the vent connector shall be constructed of listed
double-wall type B vent material or material having
equivalent insulation qualities.
5 − Multiple appliance vents − The flow area of the largest
section of vertical vent or chimney shall not exceed 7
times the smallest listed appliance categorized vent
area, drafthood outlet area or flue collar area unless de-
signed according to approved engineering methods.
6 − The entire length of single wall metal vent connector
shall be readily accessible for inspection, cleaning,
and replacement.
14 − All venting pipe passing through floors, walls, and ceil-
ings must be installed with the listed clearance to com-
bustible materials and be fire stopped according to lo-
cal codes. In absence of local codes, refer to NFGC
(Z223.1).
7 − Single appliance venting configurations with zero lat-
eral lengths (tables 5 and 6) are assumed to have no
elbows in the vent system. For all other vent configura-
tions, the vent system is assumed to have two 90° el-
bows. For each additional 90° elbow or equivalent (for
example two 45° elbows equal one 90° elbow) beyond
two, the maximum capacity listed in the venting table
should be reduced by 10% (0.90 x maximum listed ca-
pacity).
15 − No portion of the venting system can extend into, or pass
through any circulation air duct or plenum.
16 − Vent connectors serving Category I appliances shall
not be connected to any portion of mechanical draft
systems operating under positive pressure such as
Category III or IV venting systems.
17 − If vent connectors are combined prior to entering the
common vent, the maximum common vent capacity
listed in the common venting tables must be reduced by
10%, the equivalent of one 90° elbow (0.90 x maximum
common vent capacity).
erated using a maximum horizontal vent connector
length of 1−1/2 feet (.46 m) for each inch (25 mm) of
connector diameter as follows:
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18 − The common vent diameter must always be at least as
large as the largest vent connector diameter.
19 − In no case, shall the vent connector be sized more than
two consecutive table size diameters over the size of
the draft hood outlet or flue collar outlet.
21 − When connecting this appliance to an existing dedi-
cated or common venting system, you must inspect the
venting system’s general condition and look for signs
of corrosion. The existing vent pipe size must conform
to these instructions and the provided venting tables. If
the existing venting system does not meet these re-
quirements, it must be resized.
20 − Do not install a manual damper, barometric draft regu-
lator or flue restrictor between the furnace and the
chimney.
TABLE 5
Capacity of Type B Double−Wall Vents with Type B Double−Wall Connectors
Serving a Single Category I Appliance
Vent and Connector Diameter − D (inches)
Height
H
(feet)
Lateral
L
(feet)
3 Inch
4 Inch
5 Inch
6 Inch
Appliance Input Rating in Thousands of Btu Per Hour
MIN
0
MAX
78
51
49
46
84
57
53
49
88
61
57
51
94
69
65
59
53
97
75
71
64
58
52
100
81
77
70
64
58
NR
MIN
0
MAX
152
97
MIN
0
MAX
251
157
153
149
276
178
171
164
295
194
187
176
327
226
219
206
195
349
250
242
229
217
206
374
283
275
262
249
237
214
MIN
0
MAX
375
232
227
223
415
263
255
247
447
289
280
267
502
339
330
315
301
540
377
367
351
337
322
587
432
421
405
389
374
346
0
2
13
21
25
0
18
30
36
0
27
39
47
0
32
50
59
0
6
8
4
94
6
91
0
165
109
103
98
2
12
23
28
0
16
32
39
0
25
42
51
0
28
53
64
0
5
8
0
175
118
113
104
191
136
130
121
112
202
149
143
133
124
116
213
166
160
150
141
132
113
2
12
23
30
0
17
32
41
0
23
41
54
0
26
52
67
0
10
5
10
0
2
11
22
29
35
0
15
30
40
48
0
20
39
51
61
0
22
49
64
76
0
5
15
10
15
0
2
10
21
28
34
48
0
14
29
38
46
55
0
18
38
50
59
69
0
20
47
62
73
84
0
5
20
10
15
20
0
2
9
13
28
37
44
53
73
14
36
48
57
66
88
18
45
59
70
80
104
5
21
27
33
56
NR
10
15
20
30
30
NOTE − Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other
vent configurations, the vent system is assumed to have two 90° elbows. For each additional 90° elbow or equivalent (for example two 45°
elbows equal one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.90 x maxi-
mum listed capacity).
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TABLE 6
Capacity of Type B Double−Wall Vents with Single−Wall Metal Connectors
Serving a Single Category I Appliance
Vent and Connector Diameter − D (inches)
Height
H
(feet)
Lateral
L
(feet)
3 Inch
4 Inch
5 Inch
6 Inch
Appliance Input Rating in Thousands of Btu Per Hour
MIN
38
MAX
77
MIN
59
60
74
83
58
59
77
90
57
59
76
97
56
57
75
95
NR
54
56
73
93
NR
NR
53
55
72
91
115
NR
NR
MAX
151
96
MIN
85
MAX
249
156
152
147
273
176
168
161
293
193
185
171
325
225
216
201
186
346
248
239
223
208
192
372
281
271
255
239
223
NR
MIN
126
123
146
163
123
121
151
175
120
119
148
188
116
115
144
182
220
114
113
141
177
216
254
110
109
136
171
208
246
NR
MAX
373
231
225
220
412
261
252
243
444
287
277
261
499
337
326
308
290
537
375
363
344
325
306
584
429
417
397
377
357
NR
0
2
39
51
85
6
8
4
NR
NR
37
NR
NR
83
92
102
114
83
6
89
0
164
108
102
95
2
39
56
83
5
NR
NR
37
NR
NR
87
107
122
82
8
0
174
117
111
100
190
136
128
116
NR
200
148
140
129
NR
NR
211
164
157
144
131
NR
NR
2
39
61
82
10
5
52
56
105
132
80
10
0
NR
36
NR
93
2
38
69
80
5
51
63
102
128
158
78
15
10
15
0
NR
NR
35
NR
NR
96
2
37
74
78
5
50
68
100
125
155
186
76
20
10
15
20
0
NR
NR
NR
34
NR
NR
NR
99
2
37
80
76
5
49
74
98
10
15
20
30
NR
NR
NR
NR
NR
NR
NR
NR
122
151
181
NR
30
NOTE − Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other
vent configurations, the vent system is assumed to have two 90° elbows. For each additional 90° elbow or equivalent (for example two 45°
elbows equal one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.90 x maxi-
mum listed capacity).
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TABLE 7
Vent Connector Capacity
Type B Double−Wall Vents with Type B Double−Wall Connectors
Serving Two or More Category I Appliances
Vent and Connector Diameter − D (inches)
Vent
Height
H
Connector
Rise
3 Inch
4 Inch
5 Inch
6 Inch
R
(feet)
Appliance Input Rating in Thousands of Btu Per Hour
(feet)
MIN
22
23
24
22
23
24
22
23
24
21
22
24
21
22
23
20
21
22
MAX
37
41
44
40
44
47
43
47
50
50
53
55
54
57
60
62
64
66
MIN
35
37
38
35
36
37
34
36
37
33
35
36
33
34
35
31
33
34
MAX
66
MIN
46
48
49
49
51
53
49
51
52
47
49
51
46
48
50
45
47
48
MAX
106
121
132
114
128
139
123
136
146
142
153
163
157
167
176
181
190
198
MIN
58
60
62
64
66
67
65
67
69
64
66
68
62
64
66
60
62
64
MAX
164
183
199
176
195
210
189
206
220
220
235
248
246
259
271
288
299
309
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
75
6
81
72
80
8
87
78
86
10
15
20
30
92
89
96
102
99
105
110
113
118
123
TABLE 8
Common Vent Capacity
Type B Double−Wall Vents with Type B Double−Wall Connectors
Serving Two or More Category I Appliances
Common Vent Diameter − D (inches)
Vent
Height
H
4 Inch
5 Inch
6 Inch
7 Inch
Appliance Input Rating in Thousands of Btu Per Hour
(feet)
FAN + FAN
92
FAN + NAT
FAN + FAN
140
FAN + NAT
116
FAN + FAN
204
FAN + NAT
161
FAN + FAN
309
FAN + NAT
248
6
81
90
8
101
155
129
224
178
339
275
10
15
20
30
110
97
169
141
243
194
367
299
125
112
123
138
195
164
283
228
427
352
136
215
183
314
255
475
394
152
244
210
361
297
547
459
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TABLE 9
Vent Connector Capacity
Type B Double−Wall Vents with Single−Wall Metal Connectors
Serving Two or More Category I Appliances
Vent and Connector Diameter − D (inches)
Height
H
(feet)
Lateral
L
(feet)
3 Inch
4 Inch
5 Inch
6 Inch
Appliance Input Rating in Thousands of Btu Per Hour
MIN
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
49
MAX
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
NR
56
MIN
NR
NR
NR
NR
NR
NR
NR
84
MAX
NR
NR
NR
NR
NR
NR
NR
85
MIN
NR
MAX
NR
MIN
NR
MAX
NR
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
NR
NR
168
175
NR
182
198
NR
6
121
NR
131
NA
125
130
119
124
129
116
121
127
115
120
125
112
117
122
126
138
121
134
144
138
150
160
152
163
172
175
185
193
184
191
182
189
197
177
185
193
175
182
190
169
177
185
193
208
186
203
217
214
230
243
238
252
264
278
290
300
8
10
15
20
30
89
91
79
87
83
94
87
100
97
78
52
59
82
103
107
110
115
119
55
62
87
47
60
77
51
62
81
54
64
85
NOTE − Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other
vent configurations, the vent system is assumed to have two 90° elbows. For each additional 90° elbow or equivalent (for example two 45°
elbows equal one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.90 x maxi-
mum listed capacity).
TABLE 10
Common Vent Capacity
Type B Double−Wall Vents with Single−Wall Metal Connectors
Serving Two or More Category I Appliances
Common Vent Diameter − D (inches)
Vent
4 Inch
5 Inch
6 Inch
7 Inch
Height
H
(feet)
Appliance Input Rating in Thousands of Btu Per Hour
FAN + FAN
FAN + NAT
FAN + FAN
NA
FAN + NAT
113
FAN + FAN
200
FAN + NAT
158
FAN + FAN
FAN + NAT
244
6
NA
NA
78
87
304
331
357
416
463
533
8
NA
126
218
173
269
10
15
20
30
NA
94
163
137
237
189
292
121
131
145
108
118
132
189
159
275
221
343
208
177
305
247
383
236
202
350
286
446
Page 18
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Removal of the Furnace from Common Vent
7 − If a venting problem is found during any of the preced-
ing tests, the common venting system must be modi-
fied to correct the problem.
In the event that an existing furnace is removed from a
venting system commonly run with separate gas ap-
pliances, the venting system is likely to be too large to
properly vent the remaining attached appliances.
Resize the common venting system to the minimum
vent pipe size determined by using the appropriate
tables in Appendix G. (These are in the current stan-
dards of the National Fuel Gas Code ANSI Z223.1.
Conduct the following test while each appliance is operat-
ing and the other appliances (which are not operating) re-
main connected to the common venting system. If the
venting system has been installed improperly, you must
correct the system as indicated in the general venting re-
quirements section.
Gas Piping
CAUTION
WARNING
CARBON MONOXIDE POISONING HAZARD
If a flexible gas connector is required or allowed by
the authority that has jurisdiction, black iron pipe
shall be installed at the gas valve and extend outside
the furnace cabinet. The flexible connector can then
be added between the black iron pipe and the gas
supply line.
Failure to follow the steps outlined below for each
appliance connected to the venting system being
placed into operation could result in carbon mon-
oxide poisoning or death.
The following steps shall be followed for each ap-
pliance connected to the venting system being
placed into operation, while all other appliances
connected to the venting system are not in
operation:
Gas Supply
1 − This unit is shipped standard for left or right side instal-
lation of gas piping. Connect the gas supply to the pip-
ing assembly.
1 − Seal any unused openings in the common venting sys-
tem.
2 − When connecting the gas supply piping, consider fac-
tors such as length of run, number of fittings, and fur-
lists recommended pipe sizes for typical applications.
2 − Inspect the venting system for proper size and horizontal
pitch. Determine that there is no blockage, restriction,
leakage, corrosion, or other deficiencies which could
cause an unsafe condition.
3 − The gas piping must not run in or through air ducts,
clothes chutes, gas vents or chimneys, dumb waiters,
or elevator shafts.
3 − Close all building doors and windows and all doors be-
tween the space in which the appliances remaining
connected to the common venting system are located
and other spaces of the building. Turn on clothes dry-
ers and any appliances not connected to the common
venting system. Turn on any exhaust fans, such as
range hoods and bathroom exhausts, so they will oper-
ate at maximum speed. Do not operate a summer ex-
haust fan. Close fireplace dampers.
4 − The piping should be sloped 1/4 inch (6.4 mm) per 15
feet (4.57 m) upward toward the meter from the fur-
nace. The piping must be supported at proper intervals
[every 8 to 10 feet (2.44 to 3.01 m)] with suitable hang-
ers or straps. Install a drip leg inside vertical pipe runs
to the unit.
5 − A 1/8" N.P.T. plugged tap or pressure post is located
on the gas valve to facilitate test gauge connection.
4 − Follow the lighting instructions. Turn on the appliance
that is being inspected. Adjust the thermostat so that
the appliance operates continuously.
6 − In some localities, codes may require the installation of
a manual main shut-off valve and union (furnished by
the installer) external to the unit. The union must be of
the ground joint type.
5 − After the main burner has operated for 5 minutes, test
for leaks of flue gases at the draft hood relief opening.
Use the flame of a match or candle, or smoke from a
cigarette, cigar, or pipe.
6 − After determining that each appliance connected to the
common venting system is venting properly, (step 3)
return all doors, widows, exhaust fans, fireplace damp-
ers, and any other gas−burning appliances to their pre-
vious mode of operation.
IMPORTANT
Compounds used on threaded joints of gas piping
must be resistant to the actions of liquified petro-
leum gases.
Page 19
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TABLE 11
3
3
Gas Pipe Capacity − ft /hr (m /hr)
Nominal
Iron Pipe
Size
inches
(mm)
Length of Pipe − feet (m)
Internal
Diameter
inches
(mm)
10
(3.048)
20
(6.096)
30
(9.144)
40
50
60
70
80
90
100
(12.192) (15.240) (18.288) (21.336) (24.384) (27.432) (30.480)
1/2
(12.7)
.622
(17.799)
175
(4.96)
120
(3.40)
97
(2.75)
82
(2.32)
73
(2.07)
66
(1.87)
61
(1.73)
57
(1.61)
53
(1.50)
50
(1.42)
3/4
(19.05)
.824
(20.930)
360
(10.19)
250
(7.08)
200
(5.66)
170
(4.81)
151
(4.28)
138
(3.91)
125
(3.54)
118
(3.34)
110
(3.11)
103
(2.92)
1
(25.4)
1.049
(26.645)
680 465
(919.25) (13.17)
375
(10.62)
320
(9.06)
285
(8.07)
260
(7.36)
240
(6.80)
220
(6.23)
205
(5.80)
195
(5.52)
1−1/4
(31.75)
1.380
(35.052)
1400
(39.64)
950
(26.90)
770
(21.80)
660
(18.69)
580
(16.42)
530
(15.01)
490
(13.87)
460
(13.03)
430
(12.18)
400
(11.33)
1−1/2
(38.1)
1.610
(40.894)
2100
(59.46)
460
(41.34)
1180
(33.41)
990
(28.03)
900
(25.48)
810
(22.94)
750
(21.24)
690
(19.54)
650
(18.41)
620
(17.56)
2
(50.8)
2.067
(52.502)
3950
(111.85)
2750
(77.87)
2200
(62.30)
1900
(53.80)
1680
(47.57)
1520
(43.04)
1400
(39.64)
1300
(36.81)
1220
(34.55)
1150
(32.56)
2−1/2
(63.5)
2.469
(67.713)
6300 4350
(178.39) (123.17)
3520
(99.67)
3000
(84.95
2650
(75.04)
2400
(67.96)
2250
(63.71)
2050
(58.05)
1950
(55.22)
1850
(52.38)
3
(76.2)
3.068
(77.927)
11000 7700
(311.48) (218.03) (176.98) (150.07) (134.50) (121.76) (110.43) (104.77)
6250
5300
4750
4300
3900
3700
3450
(97.69)
3250
(92.03)
3
NOTE − Capacity given in cubic feet (m ) of gas per hour and based on 0.60 specific gravity gas.
MANUAL
MAIN SHUT−OFF
VALVE
Left Side Piping
(Standard)
AUTOMATIC
GAS VALVE
(with manual
shut−off valve)
AUTOMATIC
GAS VALVE
(with manual
shut−off valve)
MANUAL
MAIN SHUT−OFF
VALVE
GROUND
JOINT
UNION
GROUND
JOINT
UNION
DRIP LEG
Right Side Piping
(Alternate)
FIELD
PROVIDED
AND INSTALLED
DRIP LEG
NOTE − BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET
FIGURE 17
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Leak Check
®
for icomfort Touch thermostat wiring in communicating
After gas piping is completed, carefully check all piping
connections (factory− and field−installed) for gas leaks. Use
a leak detecting solution or other preferred means.
settings for non−communicating thermostat applications.
NOTE − If emergency shutoff is necessary, shut off the main
manual gas valve and disconnect the main power to the
furnace. The installer should properly label these devices.
INTERIOR MAKE−UP BOX INSTALLATION
(Left Side)
CAUTION
Some soaps used for leak detection are corrosive to
certain metals. Carefully rinse piping thoroughly af-
ter leak test has been completed. Do not use
matches, candles, flame or other sources of ignition
to check for gas leaks.
MAKE−UP
BOX
The furnace must be isolated from the gas supply system
by closing its individual manual shut-off valve during any
pressure testing of the gas supply system at pressuresless
than or equal to 1/2 psig (3.48 kPa, 14 inches w.c.).
FIGURE 19
IMPORTANT
When testing pressure of gas lines, gas valve must
valves can be damaged if subjected to pressures
greater than 1/2 psig (3.48 kPa, 14 inches w.c.).
INTERIOR MAKE−UP BOX INSTALLATION
(Right Side)
MANUAL MAIN
SHUT−OFF VALVE
ISOLATE
WILL NOT HOLD
GAS VALVE
NORMAL TEST
PRESSURE
FURNACE
1/8 NPT PLUG
CAP
MAKE−UP
BOX
FIGURE 18
Electrical
Cut the two wire ties to extend power wires for right side only
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
FIGURE 20
1 − The power supply wiring must meet Class I restric-
tions. Protected by either a fuse or circuit breaker, se-
lect circuit protection and wire size according to unit
nameplate.
CAUTION
Electrostatic discharge can affect elec-
tronic components. Take precautions to
neutralize electrostatic charge by
touching your hand and tools to metal
prior to handling the control.
NOTE − Unit nameplate states maximum current draw.
Maximum over−current protection allowed is shown in table
The unit is equipped with a field make−up box on the left
hand side of the cabinet. The make−up box may be moved
to the right side of the furnace to facilitate installation. If the
make−up box is moved to the right hand side, clip the wire
ties that bundle the wires together. Secure the excess wire
to the existing harness to protect it from damage.
TABLE 12
Maximum Over−Current
SL280DF Model
Protection (Amps)
070V36A
15
20
090V48B, 090V60C, 110V60C
Page 21
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Non−Communicating
2 − Holes are on both sides of the furnace cabinet to facili-
tate wiring.
In non−communicating applications the SL280DFV is de-
signed to operate in a SINGLE−STAGE mode or TWO−
STAGE mode using a conventional thermostat.
3 − Install a separate (properly sized) disconnect switch
near the furnace so that power can be turned off for
servicing.
For optimal performance in non−communicating applica-
®
tions, Lennox recommends use of a ComfortSense 7000
4 − Before connecting the thermostat or the power wiring,
check to make sure the wires will be long enough for
servicing at a later date. Remove the blower access
panel to check the length of the wire.
high quality electronic digital thermostat or any other with
adjustable settings for 1st stage / 2nd stage on / off differen-
tials and adjustable stage timers.
Lennox recommends the following two−stage thermostat
settings:
First heat stage differential set to 1/2 to 1 degree F; second
heat stage differential set to 1/2 or 1 degree F; second heat
stage upstage timer disabled, or set to maximum (1 hr mini-
mum).
5 − Complete the wiring connections to the equipment.
Use the provided unit wiring diagram and the field wir-
ing diagrams shown in table 13 and figure 24. Use
18−gauge wire or larger that is suitable for Class II ra-
ting for thermostat connections.
Communicating
6 − Electrically ground the unit according to local codes or,
in the absence of local codes, according to the current
National Electric Code (ANSI/NFPA No. 70). A green
ground wire is provided in the field make−up box.
NOTE − The SL280DFV furnace contains electronic
components that are polarity sensitive. Make sure
that the furnace is wired correctly and is properly
grounded.
®
In communicating applications the icomfort Touch ther-
mostat must be used. Refer to the instructions provided
with the thermostat for installation, set−up and operation. In
communicating system all unused thermostat wire in the
wire bundle needs to be terminated inside and out. The ex-
tra wires can terminate on the ’C" terminal of the icomfort
t
communication terminal strip. (RSBus). Using an addition-
al wire come off "C" terminal and wire nut all the extra wires
together. Termination on the outdoor control must match
the indoor control.
7 − One line voltage ꢁACC" 1/4" spade terminal is provided
on the furnace integrated control. Any electronic air
cleaner or other accessory rated up to one amp can be
connected to this terminal with the neutral leg of the cir-
cuit being connected to the one of the provided neutral
terminal is energized when the indoor blower is operat-
ing.
Indoor Blower Speeds
Non−Communicating
1 − When the thermostat is set to ꢁFAN ON," the indoor
blower will run continuously at a field selectable per-
centage of the second−stage cooling speed when there
is no cooling or heating demand. The factory default
setting is 38% of cool speed.
8 − An unpowered, normally open (dry) set of contacts with
a 1/4" spade terminal ꢁHUM" are provided for humidifi-
er connections and may be connected to 24V or 120V.
Any humidifier rated up to one amp can be connected
to these terminals. In 120V humidifier applications the
neutral leg of the circuit can be connected to one of the
provided neutral terminals. This terminal is energized
in the heating mode.
2 − When the SL280DFV is running in the heating mode,
the indoor blower will run on the heating speed desig-
nated by the positions of DIP switches 11, 12 and 13.
First stage heating will run at 91% heat speed.
3 − When there is a cooling demand, the indoor blower will
run on the cooling speed designated by the positions
of DIP switches 5 and 6. First stage cooling will run at
70% cool speed.
9 − Install the room thermostat according to the instruc-
tions provided with the thermostat. See table 13 for
field wiring connections in varying applications. If the
furnace is being matched with a heat pump, refer to the
instruction packaged with the dual fuel thermostat.
Communicating
NOTE − When the SL280DFV is used with icomfort
®
Touch thermostat, proper indoor blower speed selec-
Thermostat Selection
tions are made by the communicating thermostat.
1 − When the thermostat is set to ꢁFAN ON," the indoor
blower will run at setting determined during system
configuration.
CAUTION
Field wiring for both communicating and non−com-
municating applications is illustrated in diagrams,
2 − When there is a heating demand the fan will run on
heating speeds for firing rate.
3 − When there is a cooling demand, the fan will run on the
first stage and second stage cooling speed set using
the icomfort Touch® thermostat in the installer setup
mode. The factory default is based upon 400 CFM a
ton.
Page 22
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Generator Use − Voltage Requirements
S
S
The furnace integrated control requires both correct
polarity and proper ground. Both polarity and proper
grounding should be checked before attempting to op-
erate the furnace on either permanent or temporary
power
The following requirements must be kept in mind when
specifying a generator for use with this equipment:
S
The furnace requires 120 volts (Range: 102 volts to
132 volts)
Generator should have a wave form distortion of less
than 5% THD (total harmonic distortion)
S
The furnace operates at 60 Hz + 5% (Range: 57 Hz to
63 Hz)
®
®
icomfort Touch Thermostat with SL280DFV
and Non−Communicating Outdoor Unit
icomfort Touch Thermostat with SL280DFV
and icomfortt−ENABLED Outdoor Unit
®
®
icomfort Touch Thermostat
icomfortt−Enabled SL280DFV Indoor Furnace
Non−Communicating Outdoor Air Conditioner
icomfort Touch Thermostat
icomfortt−Enabled SL280DFV Indoor Furnace
icomfortt−Enabled Outdoor Air Conditioner or Heat Pump
icomfortt−
ENABLED
SL280DFV
icomfortt−
ENABLED
SL280DFV
FURNACE
FURNACE
OPTIONAL
DISCHARGE
AIR SENSOR
OPTIONAL
DISCHARGE
AIR SENSOR
OPTIONAL
OUTDOOR
AIR SENSOR
OPTIONAL
OUTDOOR
AIR SENSOR
icomfort Touch®
THERMOSTAT
icomfort Touch®
THERMOSTAT
icomfortt− ENABLED
OUTDOOR AIR CONDITIONING
OR HEAT PUMP UNIT
NON−COMMUNICATING
OUTDOOR AIR
CONDITIONING UNIT −
1 OR 2 STAGE
CLIP ON−BOARD LINK
W915 (Y1 TO Y2) FOR
TWO−STAGE OPERATION
NOTE − On communicating systems, extra wires must terminate on the "C" RSBus terminal. Use an additional wire and come
off "C" terminal and wire nut all the extra wires together. Termination on the outdoor control must match the indoor control.
icomfortt Integrated Control
Outdoor Unit
®
icomfort Touch
FIGURE 21
Page 23
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®
Optional Accessories for use with any icomfort Touch System
®
NOTE: icomfort Touch THERMOSTAT SENSES HUMIDITY
& CONTROLS HUM CONTACTS TO CYCLE HUMIDIFIER
BASED ON DEMAND. NO OTHER CONTROL OR HUMIDIS-
TAT REQUIRED.
120V CONNECTIONS
ꢀHUM" CONTACT IS
CLOSED ANYTIME
HUMIDITY DEMAND
IS PRESENT
OPTIONAL OUTDOOR AIR SENSOR FOR USE WITH HU-
MIDIFIER (IF NOT ALREADY IN THE SYSTEM FOR OTHER
FUNCTIONS. BUILT INTO ALL icomfort by Lennoxt OUT-
DOOR UNITS).
icomfortt ENABLED
SL280DFV FURNACE
24V HUMIDIFIER CONNECTIONS
Discharge Air
Sensor (Required
for even heat)
CS 7000
THERMOSTAT
®
icomfort Touch
THERMOSTAT
CONVENTIONAL
NON−COMMUNI-
CATING SYSTEM
RSBus
Maximum total
COMMUNICATING SYSTEM
length of all con-
nections on the
RSBus is limited
to 1500ft.
*24V IN jumper not used in non−
communicating configuration
Wire gauge of
RSBus wire is 18.
*24V IN
JUMPER
icomfortt ENABLED
SL280DFV FURNACE
NOTE: 24V UV LIGHT
APPLICATIONS
In an icomfort by Lennoxt system,
neither furnace nor air handler trans-
former will have adequate VA to
power 24V UV light applications. An
additional transformer for UV light
applications is required.
®
icomfort Touch
THERMOSTAT
icomfort
t
ENABLED OUTDOOR
AIR CONDITIONING OR
HEAT PUMP UNIT
DEHUMIDIFIER
CONTROL
(POWER COMPANY INTERRUPTION SYSTEMS
ARE WIRED SAME AS OVERFLOW SWITCH)
HVAC
EQUIPMENT
HEPA BYPASS FILTER X2680 HEPA INTERLOCK KIT
STANDARD 1 OR 2
STAGE AC OR HP UNIT
PASS INDOOR BLOWER
MOTOR COMMON WIRE
THROUGH CURRENT LOOP.
NON−COMMUNICATING
SYSTEM WIRING
SEE HEPA INTERLOCK KIT
FOR INSTALLATION DE-
TAILS
LVCS VENTILATION CONTROL SYSTEM
SEE LVCS VENTILATION
INSTRUCTIONS FOR
DAMPER & SENSOR WIRING
2 STAGE FURNACE
DS
COMMUNICATING
SYSTEM WIRING
CUT
R−DS
W914
R
FIGURE 22
Page 24
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TABLE 13
SL280 Field Wiring Applications With Conventional Thermostat
DIP Switch 1
On Board Links Must Be Cut To Select
System Options
Thermostat
Heating
Stages
Thermostat
Wiring Connections
1 Heat / 1 Cool
ON
ON
ON
S1
T’STAT
FURNACE
TERM. STRIP
OUTDOOR
UNIT
NOTE − Use DIP
switch 2 to set
second−stage
heat ON delay.
OFF−7 minutes.
ON−12 minutes.
DO NOT CUT ANY
ON−BOARD LINKS
*
1 Heat / 2 Cool
S1
T’STAT
FURNACE
TERM. STRIP
OUTDOOR
UNIT
NOTE − Use DIP
switch 2 to set
second−stage
heat ON delay.
OFF−7 minutes.
ON−12 minutes.
CUT ON−BOARD LINK
W915
2 STAGE
*
COMPR
1 Heat / 2 Cool
with t’stat with
humidity control
S1
T’STAT
FURNACE
TERM. STRIP
OUTDOOR
UNIT
CUT ON−BOARD LINK
W915
2 STAGE
COMPR
NOTE − Use DIP
switch 2 to set
second−stage
*
heat ON delay.
OFF−7 minutes.
ON−12 minutes.
CUT ON−BOARD LINK
W914
DEHUM
OR
HARMONY
o
* Not required on all units.
Page 25
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TABLE 13
SL280 Field Wiring Applications With Conventional Thermostat (Continued)
DIP Switch 1
On Board Links Must Be Cut To Select
System Options
Thermostat
Heating
Stages
Thermostat
Wiring Connections
2 Heat / 2 Cool
OFF
OFF
OFF
OFF
S1
T’STAT
FURNACE
TERM. STRIP
OUTDOOR
UNIT
CUT ON−BOARD LINK
W915
2 STAGE
COMPR
*
2 Heat / 2 Cool
with t’stat with
humidity control
S1
T’STAT
FURNACE
TERM. STRIP
OUTDOOR
UNIT
CUT ON−BOARD LINK
W915
2 STAGE
COMPR
*
CUT ON−BOARD LINK
W914
DEHUM
OR
HARMONY
o
2 Heat / 1 Cool
with t’stat with
humidity control
S1
T’STAT
FURNACE
TERM. STRIP
OUTDOOR
UNIT
CUT ON−BOARD LINK
W914
DEHUM
OR
*
HARMONY
o
2 Heat / 1 Cool
S1
T’STAT
FURNACE
TERM. STRIP
OUTDOOR
UNIT
DO NOT CUT ANY
ON−BOARD LINKS
*
* Not required on all units.
Page 26
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TABLE 13
SL280 Field Wiring Applications With Conventional Thermostat (Continued)
DIP Switch 1
Wiring Connections
Thermostat
Heating
Stages
On Board Links Must Be Cut To Select
System Options
Thermostat
FURNACE
TERM. STRIP
HEAT PUMP
Dual Fuel
Single Stage
Heat Pump
L7724U
T’STAT
OFF
H
CUT ON−BOARD LINK
W951
HEAT
PUMP
ComfortSense
7000 L7724U
thermostat w/
dual fuel capa-
bilities
67M41*
L
Y
L
Capable of 2
stage gas heat
control
Y2
D
B
Y2
T
T
outdoor
sensor
L7724U
T’STAT
FURNACE
TERM. STRIP
Dual Fuel
Two Stage
Heat Pump
HEAT PUMP
OFF
CUT ON−BOARD LINK
W915
2 STAGE
H
COMPR
67M41*
ComfortSense
7000 L7724U
thermostat w/
dual fuel capa-
bilities
Capable of 2
stage gas heat
control
CUT ON−BOARD LINK
W951
HEAT
PUMP
L
L
Y2
Y2
D
B
out blue
T
T
outdoor
sensor
* Connect W1 to W1 ONLY if using defrost tempering kit 67M41
NOTE − Do NOT make a wire connection between the room thermostat L terminal and the L terminal of the SL280
integrated control.
Page 27
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SL280 Field Wiring Applications With Conventional Thermostat (Continued)
DIP Switch 1
Wiring Connections
Thermostat
Heating
Stages
On Board Links Must Be Cut To Select
System Options
Thermostat
FURNACE
TERM. STRIP
HEAT PUMP
Dual Fuel
Single Stage
Heat Pump
L7724U
T’STAT
OFF
H
CUT ON−BOARD LINK
W951
HEAT
PUMP
ComfortSense
7000 L7724U
thermostat w/
dual fuel capa-
bilities
Capable of 2
stage gas heat
control w/dehu-
midification
control
67M41*
L
Y
L
CUT ON−BOARD LINK
W914
DEHUM
OR
Y2
HARMONY
D
B
Y2
T
T
outdoor
sensor
Dual Fuel
Two Stage
Heat Pump
L7724U
T’STAT
FURNACE
TERM. STRIP
CUT ON−BOARD LINK
W915
2 STAGE
HEAT PUMP
OFF
COMPR
H
ComfortSense
7000 L7724U
thermostat w/
dual fuel capa-
bilities
Capable of 2
stage gas heat
control w/dehu-
midification
67M41*
CUT ON−BOARD LINK
W951
HEAT
PUMP
L
L
CUT ON−BOARD LINK
W914
DEHUM
OR
Y2
Y2
HARMONY
D
B
out blue
T
T
outdoor
sensor
* Connect W1 to W1 ONLY if using defrost tempering kit 67M41
NOTE − Do NOT make a wire connection between the room thermostat L terminal and the L terminal of the SL280
integrated control.
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Integrated Control
ACC
HUM
HS/ CAI
LINE 1
NEUTRAL
7 SEGMENT LED
FLAME SENSE
INDOOR
BLOWER
CONNECTOR
DIAGNOSTIC
PUSH BUTTON
DIP SWITCHES
12 PIN LOW
VOLTAGE
CONNECTOR
OUTDOOR AIR
SENSOR
TERMINALS
DISCHARGE AIR
SENSOR
TERMINALS
W915 Y1 TO Y2
2 STAGE COMPR
W951 R TO O
HEAT PUMP
TB83
COMMUNICATING
OUTDOOR
EQUIPMENT
W914 R TO DS
DEHUM OR
HARMONY
I + I −
I + I −
R
C
R
C
C
C
TB84
W1 W2
G
Y1
R
DH
L
O
DS
Y2
COMMUNICATING
INDOOR
THERMOSTAT
NON−COMMUNICATINGNG
24V TERMINALS
RS−BUS LINK (TB82, future use)
THERMOSTAT CONNECTIONS (TB1)
DS = DEHUMIDIFICATION SIGNAL
I+ = DATA HIGH CONNECTION
I − = DATA LOW CONNECTION
W2 = HEAT DEMAND FROM 2ND STAGE T/STAT
W1 = HEAT DEMAND FROM 1ST STAGE T/STAT
R = CLASS 2 VOLTAGE TO THERMOSTAT
G = MANUAL FAN FROM T’STAT
RS−BUS OUTDOOR (TB83)
R = 24VAC
I + = DATA HIGH CONNECTION
I − = DATA LOW CONNECTION
C = 24VAXC COMMON
C = THERMOSTAT SIGNAL GROUND CONNECTED TO
TRANSFORMER GRD (TR) & CHASIS GROUND (GRD)
RS−BUS INDOOR (TB84)
Y1 = THERMOSTAT 1ST STAGE COOL SIGNAL
Y2 = THERMOSTAT 2ND STAGE COOL SIGNAL
R = 24VAC
I + = DATA HIGH CONNECTION
I − = DATA LOW CONNECTION
C = 24VAXC COMMON
O = THERMOSTAT SIGNAL TO HEAT PUMP
REVERSING VALVE
1/4" QUICK CONNECT TERMINALS
DH = DEHUMIDIFICATION OUTPUT COMMUNICATING
THERMOSTAT ONLY
HUM = UNPOWERED NORMALLY OPEN (DRY) CONTACTS
XMFR = 120 VAC OUTPUT TO TRANSFORMER
LI = 120 VAC INPUT TO CONTROL
L = USE ONLY WITH A COMMUNICATING THERMOSTAT
AND A NON−COMMUNICATING OUTDOOR UNIT
ACC = 120 VAC OUTPUT TO OPTIONAL ACCESSORY
NEUTRALS = 120 VAC NEUTRAL
FIGURE 25
. . . . . . . . . . . . .
Page 31
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supply air temperature between 90° and 110°F at the exact
moment that the blower is de−energized. Longer off delay
settings provide lower supply air temperatures; shorter set-
vides the blower off timings that will result from different
switch settings.
Integrated Control DIP Switch Settings −
Conventional Thermostat (non−communi-
cating)
SL280DFV units are equipped with a two−stage, variable
speed integrated control. This control manages ignition
timing, heating mode fan off delays and indoor blower
speeds based on selections made using the control dip
switches and jumpers. The control includes an internal
watchguard feature which automatically resets the ignition
control when it has been locked out. After one hour of con-
tinuous thermostat demand for heat, the watchguard will
break and remake thermostat demand to the furnace and
automatically reset the control to relight the furnace.
TABLE 14
Blower Off Delay Switch Settings
Blower Off Delay
(Seconds)
60
Switch 3
Switch 4
On
Off
Off
On
Off
Off
On
On
90 (Factory)
120
180
®
Note: All icomfortt settings are set at the icomfort Touch
Indoor Blower Operation DIP Switch Settings
thermostat. See icomfortt installation instruction. In icom-
fortt communication system all DIP switch and clippable
link settings are ignored. For conventional thermostats pro-
ceed with DIP switch and clippable link settings as outlined
in the following.
Switches 5 and 6 −− Cooling Mode Blower Speed −− The
unit is shipped from the factory with the dip switches posi-
tioned for high speed (4) indoor blower motor operation
mode blower speeds that will result from different switch
settings. Switches 5 and 6 set the blower cfm for second−
stage cool. The integrated control automatically ramps
down to 70% of the second−stage cfm for first−stage cfm.
Refer to tables for corresponding cfm values.
Heating Operation DIP Switch Settings
Switch 1 −− Thermostat Selection −− This unit may be used
with either a single−stage or two−stage thermostat. The
thermostat selection is made using a DIP switch which
must be properly positioned for the particular application.
The DIP switch is factory−positioned for use with a two−
stage thermostat. If a single−stage thermostat is to be used,
the DIP switch must be repositioned.
TABLE 15
Cooling Mode Blower Speeds
Speed
Low
Switch 5
On
Switch 6
On
Medium Low
Medium High
High (Factory)
Off
On
Select ꢀOFF" for two−stage heating operation con-
trolled by a two−stage heating thermostat (factory set-
ting);
On
Off
Off
Off
Switches 7 and 8 −− Cooling Blower Speed Adjustment
−− The unit is shipped from the factory with the dip switches
positioned for NORMAL (no) adjustment. The dip switches
may be positioned to adjust the blower speed by +10% or
blower speed adjustments that will result from different
switch settings. Refer to tables for corresponding cfm val-
ues.
b − Select ꢀON" for two−stage heating operation con-
trolled by a single−stage heating thermostat. This set-
ting provides a timed delay before second−stage heat
is initiated.
Switch 2 −− Second Stage Delay (Used with Single−
Stage Thermostat Only) −− This switch is used to deter-
mine the second stage on delay when a single−stage ther-
mostat is being used. The switch is factory−set in the OFF
position, which provides a 7−minute delay before second−
stage heat is initiated. If the switch is toggled to the ON
position, it will provide a 12−minute delay before second−
stage heat is initiated. This switch is only activated when
the thermostat selector jumper is positioned for SINGLE−
stage thermostat use.
TABLE 16
Cooling Blower Speed Adjustment
Adjustment
+10% (approx.)
Factory Default
−10% (approx.)
Switch 7
On
Switch 8
Off
Off
Off
Off
On
Switches 3 and 4 −− Blower−Off Delay −− The blower−on
delay of 30 seconds is not adjustable. The blower−off delay
(time that the blower operates after the heating demand
has been satisfied) can be adjusted by moving switches 3
and 4 on the integrated control. The unit is shipped from the
factory with a blower−off delay of 90 seconds. The blower
off delay affects comfort and is adjustable to satisfy individ-
ual applications. Adjust the blower off delay to achieve a
Switches 9 and 10 −− Cooling Mode Blower Speed
Ramping −− Blower speed ramping may be used to en-
hance dehumidification performance. The switches are
factory set at option A which has the greatest effect on de−
mode blower speed ramping options that will result from
different switch settings. The cooling mode blower speed
ramping options are detailed on the next page.
Page 32
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NOTE − The off portion of the selected ramp profile also ap-
plies during heat pump operation in dual fuel applications.
Ramping Option D
S
Motor runs at 100% until demand is satisfied.
Once demand is met, motor ramps down to stop.
TABLE 17
Cooling Mode Blower Speed Ramping
S
Ramping Option
Switch 9
Off
Switch 10
A (Factory)
Off
On
Off
On
100% CFM
OFF
OFF
B
C
D
Off
COMPRESSOR
DEMAND
On
On
Switches 11, 12 and 13 −− Heating Mode Blower Speed −−
The switches are factory set to the OFF position which pro-
12 and 13 that provided the corresponding increases or de-
crease to both high and low heat demand.
Ramping Option A (Factory Selection)
D Motor runs at 50% for 30 seconds.
D Motor then runs at 82% for approximately 7−1/2 minu-
tes.
D If demand has not been satisfied after 7−1/2 minutes,
motor runs at 100% until demand is satisfied.
D Once demand is met, motor runs at 50% for 30 sec-
onds then ramps down to stop.
TABLE 18
Heating Mode Blower Speeds
Switch
11
Switch
12
Switch
13
Heat Speed
Increase 24%
Increase 18%
Increase 12%
Increase 6%
On
On
On
On
Off
Off
Off
Off
On
On
Off
Off
Off
Off
On
On
On
Off
On
Off
Off
On
Off
On
7 1/2 MIN
82% CFM
100%
CFM
OFF
OFF
1/2 MIN
50% CFM
1/2 MIN
50% CFM
COMPRESSOR DEMAND
Factory Default
Decrease 6%
Decrease 12%
Decrease18%
Ramping Option B
S
S
Motor runs at 82% for approximately 7−1/2 minutes. If
demand has not been satisfied after 7−1/2 minutes,
motor runs at 100% until demand is satisfied.
Once demand is met, motor ramps down to stop.
Switches 14 and 15 −− Continuous Blower Speed −−
that will result from different switch settings.
7 1/2 MIN
82%CFM
100% CFM
OFF
OFF
COMPRESSOR DEMAND
TABLE 19
Continuous Blower Speed
Continuous
Switch 14 Switch 15
Blower Speed
Ramping Option C
Motor runs at 100% until demand is satisfied.
28% of High Cool Speed
Off
Off
On
Off
S
S
Once demand is met, motor runs at 100% for 45 sec-
onds then ramps down to stop.
38% of High Cool Speed
(Factory)
70% of High Cool Speed
100% of High Cool Speed
On
On
Off
On
100% CFM
100% CFM
45 SEC.
OFF
OFF
COMPRESSOR
DEMAND
Page 33
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minals Y1 and Y2 on the integrated control. W915 must be
cut if two−stage cooling will be used. If the Y1 to Y2 link is
not cut the outdoor unit will operate in second−stage cooling
only.
On−Board Links
Note: In icomfortt systems with a conventional outdoor
unit (non−communicating), the on−board clippable links
must be set to properly configure the system
The seven−segment diagnostic LED displays operating
status, target airflow, error codes and other information.
codes.
WARNING
Carefully review all configuration information pro-
vided. Failure to properly set DIP switches, jumpers
and on−board links can result in improper operation!
The diagnostic push button is located adjacent to the
seven−segment diagnostic LED. This button is used to en-
able the Error Code Recall ꢁE" mode and the Flame Signal
ꢁF" mode. Press the button and hold it to cycle through a
menu of options. Every five seconds a new menu item will
be displayed. When the button is released, the displayed
item will be selected. Once all items in the menu have been
displayed, the menu resumes from the beginning until the
button is released.
On−Board Link W914 Dehum or Harmony (R to DS)
On−board link W914, is a clippable connection between ter-
minals R and DS on the integrated control. W914 must be
cut when the furnace is installed with either the Harmony
IIIt zone control or a thermostat which features humidity
control. If the link is left intact the PMW signal from the Har-
mony III control will be blocked and also lead to control
damage. Refer to table 20 for operation sequence in ap-
plications including SL280DFV, a thermostat which fea-
tures humidity control and a single−speed outdoor unit.
a two−speed outdoor unit.
Error Code Recall Mode
Select "E" from the menu to access the most recent 10 error
codes. Select ꢁc" from the Error Code Recall menu to clear
all error codes. Button must be pressed a second time
while ꢁc" is flashing to confirm command to delete codes.
Press the button until a solid ꢁ≡" is displayed to exit the Error
Code Recall mode.
Flame Signal Mode
On−Board Link W951 Heat Pump (R to O)
Select "F" from the menu to access the flame signal mode.
The integrated control will display the flame current on 7
segment LED in in micro amps (uA).
On−board link W951 is a clippable connection between ter-
minals R and O on the integrated control. W951 must be cut
when the furnace is installed in applications which include a
heat pump unit and a thermostat which features dual fuel
use. If the link is left intact, terminal ꢁO" will remain ener-
gized eliminating the HEAT MODE in the heat pump.
Flame signal mode is exited after the following:
D
P
o
w
e
r
i
s
r
e
s
e
t
D Pressing and holding push button until 3 horizontal
lines ꢁ≡" are displayed
D 10 minutes of entering the flame sense mode.
On−Board Link W915 2 Stage Compr (Y1 to Y2)
On−board link W915 is a clippable connection between ter-
Page 34
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BLOWER DATA
SL280DF070V36A BLOWER PERFORMANCE (less filter)
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
HEATING
1 Heating Speed
DIP Switch
Settings
+24%
+18%
+12%
+6%
Factory Default
–6%
First Stage Heating Speed - cfm
Second Stage Heating Speed - cfm
1065
1010
960
910
860
805
755
705
1170
1115
1055
1000
945
885
830
775
–12%
–18%
COOLING
First Stage Cooling Speed - cfm
1 Cooling Speed
Second Stage Cooling Speed - cfm
Medium-Low Medium-High
DIP Switch
Settings
Low
Medium-Low Medium-High
2 High
Low
2 High
+
745
665
590
870
780
690
1025
925
815
1075
985
865
1100
1015
900
1240
1115
1025
1425
1305
1170
1515
1380
1250
Factory Default
–
1 Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specific DIP Switch
Settings.
2 Factory default setting.
NOTES - The effect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan Only speed is selectable at 28%, 38%, 70% and 100% of the selected second stage cooling speed - minimum 500 cfm.
Lennox Harmony III™ Zone Control Applications - Minimum blower speed is 425 cfm.
SL280DF090V48B BLOWER PERFORMANCE (less filter)
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
HEATING
1 Heating Speed
DIP Switch
Settings
+24%
+18%
+12%
+6%
Factory Default
–6%
First Stage Heating Speed - cfm
Second Stage Heating Speed - cfm
1360
1285
1220
1135
1075
1030
960
1500
1415
1350
1285
1200
1110
1050
975
–12%
–18%
890
COOLING
First Stage Cooling Speed - cfm
1 Cooling Speed
Second Stage Cooling Speed - cfm
Medium-Low Medium-High
DIP Switch
Settings
Low
Medium-Low Medium-High
2 High
Low
2 High
+
740
690
610
905
820
745
1040
950
855
1220
1110
1005
1085
990
895
1330
1200
1075
1545
1400
1270
1730
1,595
1460
Factory Default
–
1 Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specific DIP Switch
Settings.
2 Factory default setting.
NOTES - The effect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan Only speed is selectable at 28%, 38%, 70% and 100% of the selected second stage cooling speed - minimum 500 cfm.
Lennox Harmony III™ Zone Control Applications - Minimum blower speed is 455 cfm.
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BLOWER DATA
SL280DF090V60C BLOWER PERFORMANCE (less filter)
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
HEATING
1 Heating Speed
DIP Switch
Settings
+24%
+18%
+12%
+6%
Factory Default
–6%
First Stage Heating Speed - cfm
Second Stage Heating Speed - cfm
1540
1465
1390
1320
1245
1170
1095
1020
1695
1615
1530
1450
1365
1285
1205
1120
–12%
–18%
COOLING
First Stage Cooling Speed - cfm
1 Cooling Speed
Second Stage Cooling Speed - cfm
Medium-Low Medium-High
DIP Switch
Settings
Low
Medium-Low Medium-High
2 High
Low
2 High
+
1125
1020
900
1250
1135
1005
1400
1285
1155
1590
1445
1280
1585
1420
1305
1770
1610
1395
2000
1845
1645
2275
2,050
1875
Factory Default
–
1 Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specific DIP Switch
Settings.
2 Factory default setting.
NOTES - The effect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan Only speed is selectable at 28%, 38%, 70% and 100% of the selected second stage cooling speed - minimum 500 cfm.
Lennox Harmony III™ Zone Control Applications - Minimum blower speed is 480 cfm.
SL280DF110V60C BLOWER PERFORMANCE (less filter)
0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range
HEATING
1 Heating Speed
DIP Switch
Settings
+24%
+18%
+12%
+6%
Factory Default
–6%
First Stage Heating Speed - cfm
Second Stage Heating Speed - cfm
1645
1565
1485
1405
1325
1245
1170
1090
1810
1720
1635
1545
1460
1370
1285
1195
–12%
–18%
COOLING
First Stage Cooling Speed - cfm
1 Cooling Speed
Second Stage Cooling Speed - cfm
Medium-Low Medium-High
DIP Switch
Settings
Low
Medium-Low Medium-High
2 High
Low
2 High
+
1075
945
880
1225
1120
985
1370
1230
1135
1530
1385
1235
1500
1360
1225
1755
1585
1405
1915
1770
1595
2120
1960
1760
Factory Default
–
1 Cooling and heating speeds are based on a combination of DIP switch settings on the furnace control. Refer to Installation Instructions for specific DIP Switch
Settings.
2 Factory default setting.
NOTES - The effect of static pressure is included in air volumes shown.
First stage HEAT is approximately 91% of the same second stage HEAT.
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan Only speed is selectable at 28%, 38%, 70% and 100% of the selected second stage cooling speed - minimum 500 cfm.
Lennox Harmony III™ Zone Control Applications - Minimum blower speed is 485 cfm.
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TABLE 20
SL280DFV, Non−Communicating Thermostat with Humidity Control Feature and Single−Speed Outdoor Unit
OPERATING
SEQUENCE
SYSTEM DEMAND
Thermostat Demand Relative Humidity
SYSTEM RESPONSE
Blower
CFM
(COOL)
System
Condition
Step
Compressor
Comments
W
1
Y1
O
G
Status
D
NO CALL FOR DEHUMIDIFICATION
Normal Operation On On On
BASIC MODE (only active on a Y1 thermostat demand)
Compressor and indoor
blower follow thermostat
demand
24
VAC
1
Acceptable
High
100%
24
VAC
®
ComfortSense 7000
Normal Operation
1
2
On On On
On On On
Acceptable
Demand
High
High
100%
70%*
thermostat energizes Y1
and de−energizes D on a
call for de−humidification
Dehumidification
Call
0
VAC
PRECISION MODE (operates independent of a Y1 thermostat demand)
24
VAC
Normal Operation
1
2
On On On
On On On
Acceptable
Demand
High
High
100%
70%*
Dehumidification mode
begins when humidity is
greater than set point
Dehumidification
call
0
VAC
®
ComfortSense 7000
Dehumidification
call ONLY
0
VAC
1
On On On
Demand
High
70%*
thermostat will try to main-
tain room humidity set-
point by allowing the room
space to maintain a cooler
room thermostat set-
point**
Jumpers at indoor unit with a single stage outdoor unit
With Condensing unit − Cut W914 (R to DS) on SureLight board
With Heat Pump − Cut W914 (R to DS) & W951 (R to O) on SureLight board
®
®
®
ComfortSense 7000 thermostat to use for this application − Y2081 4 heat / 2 cool
*Dehumidification blower speed is 70% of COOL speed for all units .
®
**In Precision mode, ComfortSense 7000 thermostat will maintain room temperature up to 2 °F (1.2°C) cooler than room
setting.
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TABLE 21
SL280DFV, Non−Communicating Thermostat with Humidity Control Feature and Two−Speed Outdoor Unit
OPERATING
SEQUENCE
SYSTEM DEMAND
Thermostat Demand Relative Humidity
SYSTEM RESPONSE
Blower
CFM
(COOL)
System
Condition
Step
Compressor
Comments
W
1
W
2
Y1 Y2
O
G
Status
D
NO CALL FOR DEHUMIDIFICATION
Normal Operation −
Y1
24
VAC
1
2
On
On On
Acceptable
Acceptable
Low
70%*
100%
Compressor and indoor
blower follow thermostat
demand
Normal Operation −
Y2
24
VAC
On On On On
High
ROOM THERMOSTAT CALLS FOR FIRST STAGE COOLING
BASIC MODE (only active on a Y1 thermostat demand)
24
VAC
®
ComfortSense 7000
Normal Operation
1
2
On
On On
Acceptable
Demand
Low
70%*
thermostat energizes Y2
and de−energizes D on a
call for de−humidification
Dehumidification
Call
0
VAC
On On On On
High
70%**
PRECISION MODE (operates independent of a Y1 thermostat demand)
24
VAC
Normal Operation
1
2
On
On On
Acceptable
Demand
Low
70%*
Dehumidification mode
begins when humidity is
greater than set point
Dehumidification
call
0
VAC
On On On On
High
70%**
®
ComfortSense 7000
thermostat will try to
maintain room humidity
setpoint by allowing the
room space to maintain
a cooler room thermostat
setpoint***
Dehumidification
call ONLY
0
VAC
1
On On On On
Demand
High
70%**
ROOM THERMOSTAT CALLS FOR FIRST AND SECOND STAGE COOLING
BASIC MODE (only active on a Y1 thermostat demand)
24
VAC
®
ComfortSense 7000
Normal Operation
1
2
On On On On
On On On On
Acceptable
Demand
High
High
100%
70%**
thermostat energizes Y2
and de−energizes D on a
call for de−humidification
Dehumidification
Call
0
VAC
PRECISION MODE (operates independent of a Y1 thermostat demand)
24
VAC
Normal Operation
1
2
On
On On
Acceptable
Demand
Low
70%*
Dehumidification mode
begins when humidity is
greater than set point
Dehumidification
call
0
VAC
On On On On
On On On On
High
70%**
®
ComfortSense 7000
Dehumidification
call ONLY
0
VAC
1
Demand
High
70%**
thermostat will try to
maintain room humidity
setpoint by allowing the
room space to maintain
a cooler room thermostat
setpoint***
Jumpers at indoor unit with a two stage outdoor unit
Cut factory jumper from Y1 to Y2 or cut W915 (Y1 to Y2)
With Condensing unit − Cut W914 (R to DS) on SureLight board
With Heat Pump − Cut W914 (R to DS) & W951 (R to O) on SureLight control
®
®
®
ComfortSense 7000 thermostat to use for this application − Y2081 4 heat / 2 cool
*Normal operation first stage cooling blower speed is 70% COOL speed.
**Dehumidification blower speed is, reduced to 70% of COOL.
®
***In Precision mode, ComfortSense 7000 thermostat will maintain room temperature up to 2 °F (1.2°C) cooler than room
setting.
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1 − STOP! Read the safety information at the beginning of
this section.
Unit Start−Up
FOR YOUR SAFETY READ BEFORE LIGHTING
2 − Set the thermostat to the lowest setting.
3 − Turn off all electrical power to the unit.
4 − This furnace is equipped with an ignition device which
automatically lights the burners. Do not try to light the
burners by hand.
WARNING
Do not use this furnace if any part has been underwa-
ter. Immediately call a licensed professional service
technician (or equivalent) to inspect the furnace and
to replace any part of the control system and any gas
control which has been under water.
5 − Remove the access panel.
6 − Move switch on gas valve to OFF. Do not force. See
7 − Wait five minutes to clear out any gas. If you then smell
gas, STOP! Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s instruc-
tions. If you do not smell gas go to next step.
WARNING
If overheating occurs or if gas supply fails to shut off,
shut off the manual gas valve to the appliance before
shutting off electrical supply.
WHITE RODGERS GAS VALVE
HIGH FIRE ADJUSTMENT
SCREW
(under cap)
MANIFOLD
PRESSURE TAP
INLET PRESSURE POST
CAUTION
Before attempting to perform any service or mainte-
nance, turn the electrical power to unit OFF at dis-
connect switch.
WARNING
During blower operation, the ECM motor emits ener-
gy that may interfere with pacemaker operation. In-
terference is reduced by both the sheet metal cabinet
and distance.
GAS VALVE SHOWN IN ON POSITION
FIGURE 26
HONEYWELL GAS VALVE
HIGH FIRE
BEFORE LIGHTING smell all around the appliance area for
gas. Be sure to smell next to the floor because some gas is
heavier than air and will settle on the floor.
INLET PRESSURE TAP
ON SIDE
ADJUSTING SCREW
(under cap)
The gas valve on the SL280DFV unit will be equipped with
either a gas control switch. Use only your hand to move the
control switch. Never use tools. If the switch will not turn or if
the switch will not move by hand, do not try to repair it.
Force or attempted repair may result in a fire or explosion.
Placing the furnace into operation:
SL280DFV units are equipped with an automatic ignition
system. Do not attempt to manually light burners on these
furnaces. Each time the thermostat calls for heat, the
burners will automatically light. The ignitor does not get
hot when there is no call for heat on units with an automatic
ignition system.
MANIFOLD
PRESSURE
TAP ON
SIDE
GAS VALVE SHOWN IN ON POSITION
FIGURE 27
8 − Move switch on gas valve to ON. Do not force. See fig-
9 − Replace the access panel.
10 − Turn on all electrical power to to the unit.
11 − Set the thermostat to desired setting.
WARNING
If you do not follow these instructions exactly, a fire
or explosion may result causing property damage,
personal injury or death.
NOTE − When unit is initially started, steps 1 through 11
may need to be repeated to purge air from gas line.
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12− If the appliance will not operate, follow the instructions
ꢁTurning Off Gas to Unit" and call your service techni-
cian or gas supplier.
TABLE 22
GAS METER CLOCKING CHART
Seconds for One Revolution
Natural
LP
SL280
Unit
Turning Off Gas to Unit
1 cu ft
Dial
2 cu ft
Dial
1 cu ft
Dial
2 cu ft
DIAL
1 − Set the thermostat to the lowest setting.
2 − Turn off all electrical power to the unit if service is to be
performed.
−045
−70
80
160
110
82
200
136
102
82
400
272
204
164
136
55
3 − Remove the upper access panel.
−90
41
4 − Move switch on gas valve to OF. Do not force. See fig-
−110
−135
33
66
27
54
68
5 − Replace the upper access panel.
Natural−1000 btu/cu ft
LP−2500 btu/cu ft
Failure To Operate
If the unit fails to operate, check the following:
1 − Is the thermostat calling for heat?
Supply Line Pressure
White Rodgers Gas Valve
An inlet post located on the gas valve provides access to
screw one turn, connect a piece of 5/16 tubing and connect
to a manometer to measure supply pressure. See table 24
for supply line pressure.
2 − Are access panels securely in place?
3 − Is the main disconnect switch closed?
4 − Is there a blown fuse or tripped circuit breaker?
5 − Is the filter dirty or plugged? Dirty or plugged filters will
cause the limit control to shut the unit off.
6 − Is gas turned on at the meter?
Honeywell Gas Valve
A threaded plug on the inlet side of the gas valve provides
access to the supply pressure tap. Remove the threaded
plug, install a field−provided barbed fitting and connect a
manometer to measure supply pressure. See table 24 for
supply line pressure. Replace the threaded plug after mea-
surements have been taken.
7 − Is the manual main shut-off valve open?
8 − Is the internal manual shut-off valve open?
9 − Is the unit ignition system in lock out? If the unit locks out
again, call the service technician to inspect the unit for
blockages.
10 −Is pressure switch closed? Obstructed flue will cause
unit to shut off at pressure switch. Check flue and outlet
for blockages.
Manifold Pressure
NOTE − Pressure test adapter kit (10L34) is available from
Lennox to facilitate manifold pressure measurement.
11 −Is the rollout switch tripped? If the switch is tripped call
the service technician to inspect the unit.
1 − Connect test gauge to manifold pressure post (figure
Gas Pressure Adjustment
2 − Ignite unit on high fire and let run for 5 minutes to allow
for steady state conditions.
Gas Flow (Approximate)
3 − After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in table
Furnace should operate at least 5 minutes before check-
ing gas flow. Determine time in seconds for two revolu-
tions of gas through the meter. (Two revolutions assures a
more accurate time.) Divide by two and compare to time
and rate is incorrect, check gas orifices for proper size and
restriction. Remove temporary gas meter if installed.
show location of high fire adjustment screw.
5 − If an adjustment is made on high fire, re−check man-
ifold pressure on low fire. Do not adjust low fire man-
ifold pressure. If low fire manifold pressure is more
than 1/2" above or below value specified in table 24,
replace valve.
NOTE − Shut unit off and remove manometer as soon as an
accurate reading has been obtained. Take care to replace
pressure tap plug.
Proper Combustion
Furnace should operate minimum 15 minutes with correct
manifold pressure and gas flow rate before checking com-
SL280DFV models.
TABLE 23
Firing Rate
High Fire
Low Fire
CO %
2
CO %
For L.P.
For Nat
2
6.0 − 7.4
4.8 − 6.0
6.9 − 8.4
5.7 − 7.0
The carbon monoxide reading should not exceed 50 ppm.
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High Altitude
IMPORTANT
For safety, shut unit off and remove manometer as
soon as an accurate reading has been obtained.
Take care to replace pressure tap plug.
The manifold pressure, gas orifice and pressure switch
may require adjustment or replacement to ensure proper
manifold pressure, pressures switch and gas conversion
kits at all altitudes.
TABLE 24
Manifold Pressure Settings
Manifold
Pressure in.wg.
0−4500 ft.
Manifold
Pressure in.wg.
4501−7500 ft.
Manifold
Pressure in.wg.
7501 − 10,000 ft.
Supply Line
Pressure
in. w.g.
Orifice Size
7501 −
10,000 ft.
2
Unit
Input
Orifice Size
0 − 7500 ft.
Gas
1
Low
Fire
High
Fire
Low
Fire
High
Fire
Low
Fire
High
Fire
Min
Max
Natural
LP/propane3
Natural
.063
.039
.063
.039
.063
.039
.055
.037
.055
.037
.055
.037
1.7
4.9
1.7
4.9
1.7
4.9
3.5
10.0
3.5
1.6
4.9
1.5
4.9
1.5
4.9
3.4
10.0
3.0
1.7
4.9
1.7
4.9
1.7
4.9
3.5
10.0
3.5
4.5
11.0
4.5
13.0
13.0
13.0
13.0
13.0
13.0
070
090
110
LP/propane3
Natural
10.0
3.5
10.0
3.2
10.0
3.5
11.0
4.5
LP/propane3
10.0
10.0
10.0
11.0
1
2
3
This is the only permissible derate for these units.
Natural gas high altitude orifice kit required.
A natural to L.P. propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation instruction for the conversion
procedure.
NOTE − Units may be installed at altitudes up to 4500 ft. above sea level without modifications.
TABLE 25
High Altitude Pressure Switch Kits
High Altitude
Unit
Input
Pressure Switch Kit
0 − 4500 ft.
No Change
No Change
No Change
4501 − 7500 ft.
No Change
69W56
7501 − 10,000 ft.
070
090
110
73W36
73W36
73W35
69W56
TABLE 26
Honeywell Gas Valve Conversion Kits
TABLE 27
White Rodgers Gas Valve Conversion Kits
LP/Propane
LP/Propane
High Altitude
Natural Gas
Orifice Kit
High Altitude
Natural Gas
Orifice Kit
Natural Gas to
LP/ Propane Kit
Natural Gas to
LP/ Propane Kit
to
Natural Gas
Kit
to
Natural Gas
Kit
Unit
Input
Unit
Input
7501 −
10,000 ft.
7501 −
7501 −
10,000 ft.
7501 −
0 − 7500 ft.
0 − 7500 ft.
0 − 7500 ft.
0 − 7500 ft.
10,000 ft.
73W38
73W38
73W38
10,000 ft.
77W11
77W11
77W11
070
090
110
73W37
73W37
73W37
51W02
51W02
51W02
69W79
69W79
69W79
070
090
110
77W05
77W05
77W05
77W07
77W07
77W07
77W09
77W09
77W09
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sending a signal to the integrated control. The inte-
grated control runs a self-diagnostic program and
checks high temperature limit switches for normally
closed contacts and pressure switches for normally
open contacts. The combustion air inducer is ener-
gized at low speed.
Other Unit Adjustments
Primary and Secondary Limits
The primary limit is located on the heating compartment
vestibule panel. The secondary limits (if equipped) are lo-
cated in the blower compartment, attached to the back side
of the blower. These limits are factory set and require no
adjustment.
2 − Once the control receives a signal that the low pres-
sure switch has closed, the combustion air inducer be-
gins a 15−second pre−purge in low speed.
NOTE − If the low fire pressure switch does not close
the combustion air inducer will switch to high fire. After
a 15 second pre−purge the high fire pressure switch
will close and the unit will begin operation on high fire.
After 10 to 20 seconds of high fire operation the unit
will switch to low fire..
Flame Rollout Switch
This manually reset switch is located on the burner box. If
tripped, check for adequate combustion air before reset-
ting.
Pressure Switches
The pressure switch assembly (includes two switches) is
located in the heating compartment adjacent to the com-
bustion air inducer. These switches check for proper com-
bustion air inducer operation before allowing ignition trial.
The switches are factory−set and require no adjustment.
3 − After the pre−purge is complete, a 20−second initial ig-
nitor warm−up period begins. The combustion air in-
ducer continues to operate at low speed.
4 − After the 20−second warm−up period has ended, the gas
valve is energized on low fire (first stage) and ignition oc-
curs. At the same time, the control module sends a sig-
nal to begin an indoor blower 30−second ON−delay.
When the delay ends, the indoor blower motor is ener-
gized on the low fire heating speed, the HUM contacts
close energizing the humidifier and 120V ACC termi-
nal is energized. The furnace will continue this opera-
tion as long as the thermostat has a first−stage heating
demand.
Temperature Rise
Place the unit into operation with a second−stage heating de-
mand. After supply and return air temperatures have stabi-
lized, check the temperature rise. If necessary, adjust the
heating blower speed to maintain the temperature rise within
the range shown on the unit nameplate. Increase the blower
speed to decrease the temperature rise. Decrease the blow-
er speed to increase the temperature rise. Failure to properly
adjust the temperature rise may cause erratic limit operation
and may result in premature heat exchanger failure.
Thermostat Heat Anticipation
5 − If second−stage heat is required, the thermostat sec-
ond−stage heat contacts close and send a signal to the
integrated control. The integrated control initiates a
30−second second−stage recognition delay.
6 − At the end of the recognition delay, the integrated con-
trol energizes the combustion air inducer at high
speed. The control also checks the high fire (second
stage) pressure switch to make sure it is closed. The
high fire (second stage) gas valve is energized and the
indoor blower motor is energized for operation at the
high fire heating speed.
Set the heat anticipator setting (if adjustable) according to
the amp draw listed on the wiring diagram that is attached
to the unit.
Heating Sequence of Operation
Electronic Ignition
7 − When the demand for high fire (second stage) heat is
satisfied, the combustion air inducer is switched to the
low−fire heating speed and the high−fire (second
stage) gas valve is de−energized. The low−fire (first
stage) gas valve continues operation. The indoor
blower motor is switched to the low−fire heating speed.
8 − When the thermostat demand for low−fire (first stage)
heat is satisfied, the gas valve is de−energized and the
field−selected indoor blower off delay begins. The
combustion air inducer begins a 5−second post−purge
period.
The two−stage, variable speed integrated control used in
SL280DFV units has an added feature of an internal Watch-
guard control. The feature serves as an automatic reset de-
vice for ignition control lockout caused by ignition failure.
This type of lockout is usually due to low gas line pressure.
After one hour of continuous thermostat demand for heat,
the Watchguard will break and remake thermostat demand
to the furnace and automatically reset the control to begin
the ignition sequence.
NOTE − The integrated control thermostat selection DIP switch
is factory−set in the ꢀTWO−STAGE" position.
9 − When the combustion air post−purge period is com-
plete, the inducer, the HUM contacts as well as the
120V ACC terminals are de−energized. The indoor
blower is de−energized at the end of the off delay.
Applications Using a Two−Stage Thermostat
A − Heating Sequence −− Integrated Control Thermostat
Selection DIP Switch 1 OFF in ꢀTwo−Stage" Position
(Factory Setting)
1 − On a call for heat, thermostat first−stage contacts close
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Applications Using A Single−Stage Thermostat
B − Heating Sequence −− Control Thermostat Selection
DIP Switch 1 ON in ꢀSingle−Stage" Position
NOTE − In these applications, two−stage heat will be initi-
ated by the integrated control if heating demand has not
been satisfied after the field adjustable period (7 or 12 min-
utes).
1 − On a call for heat, thermostat first−stage contacts close
sending a signal to the integrated control. The inte-
grated control runs a self-diagnostic program and
checks high temperature limit switches for normally
closed contacts and pressure switches for normally
open contacts. The combustion air inducer is ener-
gized at low speed.
4 − After the 20−second warm−up period has ended, the gas
valve is energized on low fire (first stage) and ignition oc-
curs. At the same time, the control module sends a sig-
nal to begin an indoor blower 30−second ON−delay.
When the delay ends, the indoor blower motor is ener-
gized on the low fire heating speed and the HUM con-
tacts are energized. The integrated control also initi-
ates a second−stage on delay (factory−set at 7
minutes; adjustable to 12 minutes).
5 − If the heating demand continues beyond the second−
stage on delay, the integrated control energizes the
combustion air inducer at high speed. The control also
checks the high fire (second stage) pressure switch to
make sure it is closed. The high fire (second stage)
gas valve is energized and the indoor blower motor is
energized for operation at the high fire heating speed.
6 − When the thermostat heating demand is satisfied, the
combustion air inducer begins a 5−second low speed
post−purge. The field−selected indoor blower off delay
begins. The indoor blower operates at the low−fire
heating speed.
2 − Once the control receives a signal that the low pres-
sure switch has closed, the combustion air inducer be-
gins a 15−second pre−purge in low speed.
NOTE − If the low fire pressure switch does not close
the combustion air inducer will switch to high fire. After
a 15 second pre−purge the high fire pressure switch
will close and the unit will begin operation on high fire.
After 10 to 20 seconds of high fire operation the unit
will switch to low fire.
7 − When the combustion air post−purge period is com-
plete, the inducer, the HUM contacts as well as the
120V ACC terminals are de−energized. The indoor
blower is de−energized at the end of the off delay.
3 − After the pre−purge is complete, a 20−second initial ig-
nitor warm−up period begins. The combustion air in-
ducer continues to operate at low speed.
HEATING OPERATION WITH TWO−STAGE THERMOSTAT
15
1
35
39
80
5 SEC
30* second
blower
ꢀon" delay
blower
ꢀoff"
delay
ON
OFF
Trial For
Ignition
Post
Purge
Pre−Purge
Ignitor Warm−up
1 stg heat demand
low speed CAI
ignitor
low fire gas valve
indoor blower low heat
30 seconds
RECOGNITION PERIOD
2 stg heat demand
high speed CAI
high fire gas valve
indoor blower high heat
®
* Conventional thermostat 30 seconds, icomfort Touch thermostat set for 30 adjustable 15 to 45 seconds.
FIGURE 28
HEATING OPERATION WITH SINGLE STAGE THERMOSTAT
15
35
39
5 SEC
1
80
blower
ꢀoff"
delay
30* second
blower
ꢀon" delay
Trial For
Ignition
ON
Ignitor Warm−up
Pre−Purge
Post
Purge
OFF
heat demand
low speed CAI
ignitor
low fire gas valve
indoor blower low heat
7 or 12 minutes after heating demand begins, furnace switches to high fire (depends on setting)
high speed CAI
high fire gas valve
indoor blower high heat
®
* Conventional thermostat 30 seconds, icomfort Touch thermostat set for 30 adjustable 15 to 45 seconds.
FIGURE 29
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Electrical
Service
1 − Check all wiring for loose connections.
2 − Check for the correct voltage at the furnace (furnace
operating). Correct voltage is 120VAC + 10%.
3 − Check amp−draw on the blower motor with inner blow-
er access panel in place.
Unit Nameplate__________Actual__________
WARNING
ELECTRICAL SHOCK, FIRE,
OR EXPLOSION HAZARD.
Cleaning the Heat Exchanger and Burners
NOTE − Use papers or protective covering in front of the fur-
nace during cleaning.
Failure to follow safety warnings exactly could result
in dangerous operation, serious injury, death or
property damage.
Improper servicing could result in dangerous opera-
tion, serious injury, death, or property damage.
Before servicing, disconnect all electrical power to
furnace.
1 − Turn off both electrical and gas power supplies to fur-
nace.
2 − Remove flue pipe, top cap, flue chase and internal flue
pipe assembly from the unit.
3 − Label the wires from gas valve, rollout switches, prima-
ry limit switch and make−up box then disconnect them.
4 − Remove the screws that secure the combustion air in-
ducer/pressure switch assembly to the collector box.
Carefully remove the combustion air inducer to avoid
damaging blower gasket. If gasket is damaged, it must
be replaced to prevent leakage.
When servicing controls, label all wires prior to dis-
connecting. Take care to reconnect wires correctly.
Verify proper operation after servicing.
At the beginning of each heating season, a licensed profes-
sional technician (or equivalent) should check the system
as follows:
5 − Remove the collector box located behind the combus-
tion air inducer. Be careful with the collector box gas-
ket. If the gasket is damaged, it must be replaced to
prevent leakage.
Blower
Check the blower wheel for debris and clean if necessary.
The blower motors are prelubricated for extended bearing
life. No further lubrication is needed.
6 − Disconnect gas supply piping. Remove the screw se-
curing the burner box cover and remove cover. Re-
move the four screws securing the burner manifold as-
sembly to the vestibule panel and remove the
assembly from the unit.
WARNING
The blower access panel must be securely in place
when the blower and burners are operating. Gas
fumes, which could contain carbon monoxide, can
be drawn into living space resulting in personal inju-
ry or death.
7 − Remove screws securing burner box and remove
burner box.
8 − Remove screws from both sides, top and bottom of
vestibule panel.
9 − Remove heat exchanger. It may be necessary to
spread cabinet side to allow more room. If so, remove
five screws from the left side or right side of cabinet.
Filters
All SL280DFV filters are installed external to the unit. Fil-
ters should be inspected monthly. Clean or replace the fil-
ters when necessary to ensure that the furnace operates
properly. Replacement filters must be rated for high veloc-
10− Back wash using steam. Begin from the burner opening
on each clam. Steam must not exceed 275°F.
11− To clean burners, run a vacuum cleaner with a soft brush
attachment over the face of burners. Visually inspect in-
side the burners and crossovers for any blockage
caused by foreign matter. Remove any blockage. Figure
30 shows burner detail.
Flue And Chimney
1 − Check flue pipe, chimney and all connections for tight-
ness and to make sure there is no blockage.
2 − Check unit for proper draft.
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SL280DFV BURNER, COMBUSTION AIR INDUCER ASSEMBLY &
HEAT EXCHANGER REMOVAL
gasket
orifice plate
gasket
flue chase
internal flue pipe
combustion air inducer
rollout switch
ignitor
burner box assembly
collector box
pressure switch
heat exchanger
sensor
gasket
burners
manifold and gas valve
burner box cover plate
retention rings
cross over
FIGURE 30
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12− To clean the combustion air inducer visually inspect and
using a wire brush clean where necessary. Use com-
pressed air to clean off debris and any rust.
22− Repeat steps 21 and 23 until no leaks are detected.
23− Replace access panel.
13− Reinstall heat exchanger in vestibule. (Replace the
five screws in the cabinet from step 10 if removed).
Remove five screws if necessary
(either side of cabinet)
14− Reinstall collector box, combustion air assembly, inter-
nal flue pipe and flue chase. Seal with high tempera-
ture RTV. Reinstall all screws to the collector box and
combustion air inducer. Failure to replace all screws
may cause leaks. Inspect gaskets for any damage and
replace if necessary.
15− Reinstall burner box, manifold assembly and burner box
cover.
16− Reconnect all wires.
17− Reconnect top cap and vent pipe to combustion air in-
ducer outlet.
18− Reconnect gas supply piping.
19− Turn on power and gas supply to unit.
20− Set thermostat and check for proper operation.
4
20− Check all piping connections, factory and field, for gas
leaks. Use a leak detecting solution or other preferred
means.
3
5
2
1
CAUTION
Some soaps used for leak detection are corrosive to
certain metals. Carefully rinse piping thoroughly af-
ter leak test has been completed. Do not use
matches, candles, flame or other sources of ignition
to check for gas leaks.
FIGURE 31
21− If a leak is detected, shut gas and electricity off and
repair leak.
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Planned Service
The following items should be checked during an annual inspection. Power to the unit must be shut off for the service techni-
cian’s safety.
Fresh air grilles and louvers (on the unit and in the room
where the furnace is installed) − Must be open and unob-
structed to provide combustion air.
Operating performance − Unit must be observed during
operation to monitor proper performance of the unit and the
vent system.
Combustion gases − Flue products must be analyzed and
Burners − Must be inspected for rust, dirt, or signs of water.
compared to the unit specifications.
Vent pipe − Must be inspected for signs of water, damaged
Problems detected during the inspection may make it nec-
essary to temporarily shut down the furnace until the items
can be repaired or replaced.
or sagging pipe, or disconnected joints.
Unit appearance − Must be inspected for rust, dirt, signs
of water, burnt or damaged wires, or components.
Instruct the homeowners to pay attention to their
furnace. Situations can arise between annual furnace in-
spections that may result in unsafe operation. For instance,
items innocently stored next to the furnace may obstruct
the combustion air supply. This could cause incomplete
combustion and the production of carbon monoxide gas.
Blower access door − Must be properly in place and pro-
vide a seal between the return air and the room where the
furnace is installed.
Return air duct − Must be properly attached and provide
an air seal to the unit.
Repair Parts List
The following repair parts are available through independent Lennox dealers. When ordering parts, include the complete
furnace model number listed on the CSA International nameplate −− Example: SL280DF070V36A.
All service must be performed by a licensed professional installer (or equivalent), service agency, or gas supplier.
Cabinet Parts
Upper access panel
Heating Parts
Flame Sensor
Blower panel
Top cap
Heat exchanger assembly
Gas manifold
Control Panel Parts
Transformer
Two−speed combustion air inducer
Two−stage gas valve
Main burner cluster
Main burner orifices
Pressure switch
Two−stage, variable speed integrated control
Door interlock switch
Circuit breaker
Blower Parts
Ignitor
Blower wheel
Primary limit control
Flame rollout switch
Blower housing
Motor
Secondary limit
Motor electronics
Power choke (1 hp only)
Motor mounting frame
Blower housing cutoff plate
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Integrated Control Diagnostic Modes
Display
Action (when button released)
Remain in idle mode
No change (idle)*
Solid ꢁE"
Enter diagnostic recall mode
Discharge Air Installed
Solid ꢁD"
Solid ꢁF"
Enter flame signal mode
Solid ꢁP" (variable speed only)
Program unit capacity/size (Unit Code)**
* No change implies the display will continue to show whatever is currently being displayed for normal operation (blinking
decimal, active error code, heat state, etc..)
** After the ꢁP" is selected (by releasing the push button) the integrated control will start flashing the ꢁP" on display for 90
seconds. If push button is pressed again and held during that time, the control will start to display characters corresponding
to different variable speed furnace models for 3 seconds each. While the wanted character−model is displayed push button
has to be released. Selected option will flash display for 10 seconds and during that time push button has to be pressed
and held for 5 seconds. Once control accepts new setting it will store data in non−volatile memory and reset itself. If 10 sec-
onds expires or push button is held less than 5 seconds, control will exit filed test mode and go in idle without programming
the unit size.
Integrated Control Diagnostic Codes
Press the diagnostic push button and hold it to cycle through a menu of options. Every five seconds a new menu item will be
displayed. Release the button when the desired mode is displayed.
When a solid "P" is displayed, the furnace capacity / size is programmed.
When the solid ꢁE" is displayed, the control enters the Diagnostic Recall (Alarm History). Diagnostic Recall mode menu
options: No change (displaying error history) remains in Diagnostic Recall mode; solid ꢁ = " exits Diagnostic Recall mode;
and solid ꢁc" clears the error history. Must press button while flashing ꢁc" is displayed to clear error codes.
When the solid ꢁF" is displayed, the control enters the Flame Signal Mode. The Flame Signal Mode is exited: with power
cycle/reset, by pressing and holding the push button until 3 horizontal line are displayed ꢁ= ꢁ, after 10 minutes of entering
flame signal mode.
Code
Diagnostic Codes/Status of Equipment
Action Required to Clear and Recover
.
Idle mode (Decimal blinks at 1 Hertz −− 0.5 second ON, 0.5 second OFF).
A
Cubic feet per minute (cfm) setting for indoor blower (1 second ON, 0.5
second OFF) / cfm setting for current mode displayed.
C
d
Cooling stage (1 second ON, 0.5 second OFF) / 1 or 2 displayed / Pause
/ cfm setting displayed / Pause / Repeat codes).
Dehumidification mode (1 second ON) / 1 second OFF) / cfm setting dis-
played / Pause / Repeat Codes).
h
Heat pump stage (1 second ON, 0.5 second OFF) / % of input rate dis-
played / Pause / cfm setting / Pause / Repeat codes.
H
Gas Heat Stage (1 second ON, 0.5 second OFF) / 1 or 2 displayed /
Pause / cfm
setting displayed / Pause / Repeat codes. Blinking during ignition.
dF
U
Defrost mode.
Discharge Air Temperature
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Integrated Control Diagnostic Codes (continued)
Code
Diagnostic Codes/Status of Equipment
Action Required to Clear and Recover
E 105 Device communication problem − No other devices on RS BUS (Commu- Equipment is unable to communicate. Indicates
nication
system).
numerous message errors. In most cases errors are
related to electrical noise. Make sure high voltage
power is separated from RSBus. Check for mis−
wired and/or loose connections between the stat,
indoor unit and outdoor unit. Check for a high volt-
age source of noise close to the system. Fault
clears after communication is restored.
E 110 Low line voltage.
Line Voltage Low (Voltage lower than nameplate
rating). Check power line voltage and correct. Alarm
clears 5 seconds after fault recovered.
E 111 Line voltage polarity reversed.
Reverse line power voltage wiring. System resumes
normal operation 5 seconds after fault recovered.
E 112 Ground not detected
System shuts down. Provide proper earth ground.
System resumes normal operation 5 seconds after
fault recovered.
E 113 High line voltage.
Line Voltage High (Voltage higher than nameplate
rating). Provide power voltage within proper range.
System resumes normal operation 5 seconds after
fault recovered.
E 114 Line voltage frequency out−of−range.
E 115 Low 24V − Control will restart if the error recovers.
No 60 Hertz Power. Check voltage and line power
frequency. Correct voltage and frequency problems.
System resumes normal operation 5 seconds after
fault recovered.
24−Volt Power Low (Range is 18 to 30 volts). Check
and correct voltage. Check for additional power−rob-
bing equipment connected to system. May require
installation of larger VA transformer to be installed in
furnace / air handler. Clears after fault recovered.
E 116 High 24V.
24 Volt Power High (Range is 18 to 30 volts). Check
and correct voltage. Check for proper line voltage
(120V, 240V, etc.) to equipment. Clears when con-
trol senses proper voltage.
E 117 Poor ground detected (Warning only)
Provide proper grounding for unit. Check for proper
earth ground to the system. Warning only will clear
30 seconds after fault recovered.
E 120 Unresponsive device. Communication only.
Usually caused by delay in outdoor unit responding
to indoor unit poling. Recycle power. Check all wir-
ing connections. Cleared after unresponsive device
responds to any inquiry.
E 124 Active communicating thermostat signal missing for more than 3 min-
utes.
Equipment lost communication with the thermostat.
Check four wiring connections, ohm wires and cycle
power at the thermostat. Alert stops all services and
waits for heartbeat message from thermostat (sub-
net controller). Cleared after valid thermostat (sub-
net controller) message is received.
E 125 Control failed self−check, internal error, failed hardware. Will restart if
error
Hardware problem on the control. Cycle power on
control. Replace if problem prevents service and is
recovers. Integrated control not communicating. Covers hardware errors persistent. Critical alert. Cleared 300 seconds after
(flame sense circuit faults, pin shorts, etc.).
fault recovered.
E 126 Control internal communication problem.
Hardware problem on the control. Cycle power on
control. Replace if problem prevents service and is
persistent. Cleared 300 seconds after fault recov-
ered.
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Integrated Control Diagnostic Codes (continued)
E 131 Corrupted control parameters (Verify configuration of system). Communi- Reconfigure the system. Replace control if heating
cating only.
or cooling is not available. Only applicable in the
communicating mode, not in startup. Exit from Com-
missioning and Execute ’Set Factory Default mode’.
Control will still operate on default parameter set-
tings.
E 180 Outdoor air temperature sensor failure. Only shown if shorted or out−of−
range.
Compare outdoor sensor resistance to temperature/
resistance charts in unit installation instructions.
Replace sensor pack if necessary. At beginning of
(any) configuration, furnace or air handler control
will sense outdoor air and discharge air temperature
sensor(s). If detected (reading in range), appropri-
ate feature will be set as ’installed’ and that could
be seen in ’About’ screen. In normal operation after
control recognizes sensors, alarm will be sent if
valid temperature reading is lost. To get rid of set-
ting and alarm, redo configuration and make sure
that temperature sensor is marked as ’not installed’
in Indoor Unit ’About’ screen. When Indoor unit con-
trol is replaced, thermostat will ’tell’ new control if
temperature sensor is in system or not. Clears 30
seconds after fault recovered.
E 200 Hard lockout − Rollout circuit open or previously open.
Correct cause of rollout trip, or replace flame rollout
switch. Test furnace operation. Cleared after fault
recovered.
E 201 Indoor blower communication failure − Unable to communicate with blow- Indoor blower communication failure (including pow-
er motor.
er outage). Lost communication with indoor blower
motor. Possible causes: motor not powered, loose
wiring. Problem may be on control or motor side.
Cleared after fault recovered.
E 202 Indoor blower motor mis−match − Indoor motor horsepower does not
match unit capacity. See Page 55.
Incorrect appliance capacity code selected. Check
for proper configuring under: Unit Size Codes for
Furnace/Air Handler on configuration guide or in
installation instructions. Cleared after the correct
match is detected following a reset. (Remove ther-
mostat from system while applying power and re-
programming.)
E 203 Appliance capacity / size is NOT programmed. Invalid unit codes refer to No appliance capacity code selected. Check for
proper configuring under: Unit Size Codes for Fur-
nace on configuration guide or in installation instruc-
tions. Critical Alert. Cleared after valid unit code is
read following a reset. (Remove thermostat from
system while applying power and reprogramming.)
E 204 Gas valve mis−wired.
Check gas valve operation and wiring. Clears when
repaired.
E 205 Gas valve control relay contact shorted.
Check wiring on control and gas valve. If wiring is
correct, replace control.
st
E 206 Gas valve second−stage relay failure
Furnace will operate on 1 stage for remainder of
the heating demand. Will clear after fault recovered.
If unable to operate 2nd stage, replace control.
E 207 Hot surface ignitor sensed open − Refer to troubleshooting. See Page 56. Measure resistance of hot surface ignitor. Replace if
open or not within specified range found in IOM.
Resumes normal operation after fault is cleared.
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Integrated Control Diagnostic Codes (continued)
Code
Diagnostic Codes/Status of Equipment
Low pressure switch failed open.
Action Required to Clear and Recover
E 223
Check pressure (inches w.c.) of low pressure switch
closing on heat call. Measure operating pressure
(inches w.c.). Inspect vent and combustion air in-
ducer for correct operation and restriction. Re-
sumes normal operation after fault is cleared
E 224
Low pressure switch failed closed − Refer to troubleshooting. See
Check operation of low pressure switch to see if it is
stuck closed on heat call longer than 150 seconds.
Measure operating pressure (inches w.c.). Inspect
vent and combustion air inducer for correct opera-
tion and restriction. Resumes normal operation after
fault is cleared.
E 225
E 226
E 227
E 228
High pressure switch failed open − Refer to troubleshooting. See
Check pressure (inches w.c.) of high pressure
switch closing on heat call. Measure operating pres-
sure (inches w.c.). Inspect vent and combustion air
inducer for correct operation and restriction. Re-
sumes normal operation after fault is cleared.
High pressure switch failed closed − Refer to troubleshooting. See
Check operation of high pressure switch closing on
heat call. Measure operating pressure (inches w.c.).
Inspect vent and combustion air inducer for correct
operation and restriction. Resumes normal opera-
tion after fault is cleared.
Low pressure switch open during trial for ignition or run mode. Refer to
Check pressure (inches w.c.) of low pressure switch
closing on heat call. Measure operating pressure
(inches w.c.). Inspect vent and combustion air in-
ducer for correct operation and restriction. Re-
sumes normal operation after fault is cleared.
Combustion air inducer calibration failure
Ignition on high fire
Unable to perform pressure switch calibration.
Check vent system and pressure switch wiring con-
nections. Resumes normal operation after fault is
cleared.
E 229
E 240
IFC switched to high fire ignition because low fire
pressure switch did not close in allowed time. No
action is needed.
Low flame current − Run mode − Refer to troubleshooting. See Page 56. Check micro−amperes of flame sensor using control
diagnostics or field−installed mode. Clean or replace
sensor. Measure voltage of neutral to ground to en-
sure good unit ground. Alert clears after current
heat call has been completed.
E 241
E 250
Flame sensed out of sequence − Flame still present.
Limit switch circuit open − Refer to troubleshooting.
Shut off gas. Check for gas valve leak. Replace, if
necessary. Alert clears when fault is recovered.
Check for proper firing rate on furnace. Ensure
there is no blockage in heater. Check for proper air
flow. If limit not closed within 3 minutes, unit will go
into 1−hour soft lockout. Resumes normal operation
after fault is cleared.
E 252
E 270
Discharge air temperature too high (gas heat only).
Check temperature rise, air flow and input rate.
Cleared when heat call is finished.
Soft lockout − Exceeded maximum number of retries. No flame current
sensed.
Check for proper gas flow. Ensure that ignitor is
lighting burner. Check flame sensor current. Clears
when heat call finishes successfully.
E 271
Soft lockout − Exceeded maximum number of retries. Last retry failed due Check pressure (inches w.c.) of low pressure switch
to the pressure switch opening.
closing on heat call. Measure operating pressure
(inches w.c.). Inspect vent and combustion air in-
ducer for correct operation and restriction. Clears
when heat call finishes successfully.
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Integrated Control Diagnostic Codes (continued)
E 272
Soft lockout − Exceeded maximum number of recycles. Last recycle due
to the pressure switch opening.
Check operation of low pressure switch to see if it is
stuck closed on heat call. Check pressure (inches
w.c.) of high pressure switch closing on heat call.
Measure operating pressure (inches w.c.). Inspect
vent and combustion air inducer for correct opera-
tion and restriction. Clears when heat call finishes
successfully.
E 273
E 274
Soft lockout − Exceeded maximum number of recycles. Last recycle due
to flame failure.
Check micro−amperes of flame sensor using control
diagnostics or field−installed mode. Clean or replace
sensor. Measure voltage of neutral to ground to en-
sure good unit ground. Clears when heat call finish-
es successfully.
Soft lockout − Exceeded maximum number of recycles. Last recycle
failed due to the limit circuit opening or limit remained open longer than
3 minutes.
Shut down system. 1−hour soft lockout. Check firing
rate and air flow. Check for blockage. Clears when
heat call finishes successfully.
E 275
E 276
Soft lockout − Flame sensed out of sequence. Flame signal is gone.
Shut off gas. Check for gas valve leak. 1−hour soft
lockout. Clears when flame has been proven stable.
Watchguard calibration failure.
Unable to perform pressure switch calibration.
Check vent system and pressure switch wiring con-
nections. 1−hour soft lockout. Clears when calibra-
tion has finished successfully.
E 290
E 291
E 292
Ignitor circuit fault − Failed ignitor or triggering circuitry.
Heat air flow restricted below the minimum.
Measure resistance of hot surface ignitor. Replace if
open or not within specifications. 1−hour soft lock-
out. Clears when flame has been proven stable.
Check for dirty filter and air flow restriction. Check
blower performance. 1−hour soft lockout. Cleared
when heat call finishes successfully.
Indoor blower motor unable to start due to obstructed wheel, seized
bearings.
Indoor blower motor unable to start (seized bear-
ing, stuck wheel, etc.). Replace motor or wheel if
assembly does not operate or meet performance
standards. 1−hour soft lockout. Clears after circula-
tor successfully starts.
E 294
Combustion air inducer over current.
Check combustion blower bearings, wiring and
amps. Replace if does not operate or does not meet
performance standards. Clears after inducer current
is sensed to be in−range after the ignition following
the soft lockout or reset.
E 295
E 310
Indoor blower motor temperature is too high.
Indoor blower motor over temperature (motor
tripped on internal protector). Check motor bearings
and amps. Replace if necessary. Cleared after
blower demand is satisfied.
Discharge error temperature sensor failure. Only shown if shorted or
out of range.
Compare outdoor sensor resistance to temperature/
resistance charts in installation instructions. Re-
place sensor if necessary. Cleared in Communicat-
ing mode: 30 seconds after fault recovered. In Non−
Communicating mode: Cleared after the current
heat call is completed.
E 311
Heat rate reduced to match indoor blower air flow.
Warning Only. Furnace blower in cutback mode due
to restricted airflow. Reduce firing rate every 60
seconds to match available CFM. Check filter and
duct system. To clear, replace filter if needed or re-
pair/add duct. 2−stage controls will reduce firing rate
st
to 1 stage. Clears when heat call finishes success-
fully.
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Integrated Control Diagnostic Codes (continued)
Code
Diagnostic Codes/Status of Equipment
Action Required to Clear and Recover
E 312
Restricted air flow in cooling or continuous fan mode is lower than cfm
setting.
Warning Only. Restricted airflow − Indoor blower is
running at a reduced CFM (Cutback Mode − The
variable speed motor has pre−set speed and torque
limiters to protect the motor from damage caused
by operating outside of design parameters (0 to 0.8"
W.C.. total external static pressure). Check filter and
duct system. To clear, replace filter if needed or re-
pair/add duct. Cleared after the current service de-
mand is satisfied.
E 313
Indoor or outdoor unit capacity mismatch. Communication only.
Incorrect indoor/outdoor capacity code selected.
Check for proper configuring in installation instruc-
tions. Alarm is just a warning. The system will oper-
ate, but might not meet efficiency and capacity pa-
rameters. Alarm will clear when commissioning is
exited. Cleared after commissioning is complete.
E 331
E 334
E 347
Global network connection − Communication link problem.
Relay ꢁY1" stuck on interated control.
For Future Use.
Replace integrated control.
No 24 Volt output on Y1 of "integrated control" with non communicating
outdoor unit.
Operation stopped. Y1 relay / Stage 1 failed. (Pilot
relay contacts did not close or the relay coil did not
energize; no input back to IFC chip). Critical Alert.
Cleared after reset and Y1 input sensed.
E 348
No 24 Volt output on Y2 of "integrated control" with non?communicating
outdoor unit.
Y2 relay / Stage 2 failed. (Pilot relay contacts did
not close or the relay coil did not energize; no input
back to IFC chip). Critical Alert. Cleared after reset
and Y1 input sensed.
E 349
E 370
No 24 Volts between R & O on "integrated control" with non communi-
cating outdoor unit (Dual fuel module required for heat pump application). place link or hard−wire. Applicable in non communi-
cating mode. Critical Alert.
Configuration link R to O needs to be restored. Re-
Interlock switch sensed open for 2 minutes.
LSOM − Compressor internal overload tripped.
LSOM Compressor long run cycle or low system pressure.
LSOM − Outdoor unit system pressure trip.
Control sees the loss of 24VAC for 2 minutes .Ter-
minate all services and wait for interlock switch to
close. The alarm will clear when 24VAC is continu-
ously sensed on DS terminal for a minimum of 10
seconds or on a power reset.
E 400
E 401
Thermostat demand Y1 is present; but, compressor
is not running. Check power to outdoor unit. Clears
the error after current is sensed in both RUN and
START sensors for at least 2 seconds, or after ser-
vice is removed, or after power reset.
Compressor ran more than 18 hours to satisfy a
single thermostat demand. Critical Alert. Clears the
error after 30 consecutive normal run cycles or
power reset. Also monitors low pressure switch
trips.
E 402
E 403
E 404
Discharge or suction pressure out−of−limits, or com-
pressor overloaded. Clears the error after 4 consec-
utive normal compressor run cycles.
LSOM − Compressor short−cycling. .(Running less than 4 minutes). Out-
door unit pressure trip
Compressor runs less than 3 minutes to satisfy a
thermostat demand. Clears the error after 4 consec-
utive normal run cycles or power reset.
LSOM − Compressor rotor locked. Compressor short−cycling. (Running
less than 4 minutes).
Compressor rotor locked up due to run capacitor
short, bearings are seized, excessive liquid refriger-
ant, etc. Clears the error after 4 consecutive normal
run cycles or after power reset.
E 405
LSOM − Compressor open circuit.
Compressor circuit open (due to power disconnec-
tion, open fuse, etc.) Clears the error after 1 normal
compressor run cycle.
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Integrated Control Diagnostic Codes (continued)
E 406
LSOM − Compressor open start circuit.
Required amount of current is not passing through
Start current transformer. Clears the error after cur-
rent is sensed in START sensor, or after power re-
set.
E 407
LSOM − Compressor open run circuit.
Required amount of current is not passing through
Run current transformer. Clears the error after cur-
rent is sensed in RUN sensor, or 1 normal compres-
sor run cycle, or after power reset.
E 408
E 409
LSOM − Compressor contactor is welded.
LSOM − Compressor low voltage.
Compressor runs continuously. Clears the error
after 1 normal compressor run cycle or after power
reset.
Secondary voltage is below 18VAC. After 10 min-
utes, operation is discontinued. Clears the code
after voltage is higher than 20 VAC for 2 seconds or
after power reset.
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Program Unit Capacity/Size Mode
Power−Up − Number displayed represents by integrated control unit size code (furnace model
and capacity). If three horizontal bars are displayed followed by continuous E203, furnace
control does not recognize unit size code. Configure per the following:
−
−
−
Furnace control in IDLE mode
No heating, cooling or indoor fan
operation)
No
Yes
To enter Program Unit
Capacity/Size: push
and hold button next to
7−segment LED display
until solid ꢀP" symbol
_
Turn room thermostat to OFF
appears.
button.
Release
IMPORTANT: Field replacement controls may
need to be manually configured to validate
furnace unit size code.
UNIT SIZE
CODE
FURNACE MODEL
SL280DF070V36A
SL280DF090V48B
SL280DF090V60C
SL280DF110V60C
A
b
C
d
Solid
blinking
7−Segment LED
P
starts
on
P
When the correct unit size code is displayed, release
button. Selected code will flash for 10−second period.
During that period, press and hold push button for 5
seconds. Integrated control will store code in
memory and will automatically exit Program Unit
Capacity/Size Mode and reset. (If second period
expires or push button is held less than five seconds,
Push and hold button. Integrated control will
display unit size code number for each
furnace model for three seconds.
control
will
automatically
exit
Program
Capacity/Size Mode and go into IDLE mode without
storing unit size code. If this happens, programming
function must be repeated).
−
−
Verify that the selected unit size code is correct
and stored in non−volatile memory by cycling
−
the 24 volt power to the furnace control. (At 24
volt power−up of the furnace control, the
7−segment LED will display a unit size code. If
three horizontal bars display, board does not
recognize unit size code. Programming
function must be repeated)
FINISHED
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Troubleshooting: Heating Sequence of Operation
CALL FOR FIRST−STAGE HEAT
1
CALL FOR
1ST STAGE HEAT
(LOW FIRE)
NO
INDOOR BLOWER OFF AFTER
HEAT FAN OFF DELAY
(LOW HEAT SPEED)
YES
INDOOR
BLOWER OFF
LIMIT
SWITCH
HIGH
LIMIT SWITCH
CLOSED?
ERROR
INDOOR
BLOWER
WATCHGUARD −
AFTER HEAT FAN
OFF DELAY (LOW
HEAT SPEED)
NO
NO
CODE
CLOSED WITHIN 3
MINUTES?
ERROR CODE
FLASHES
1
FLASHES
ON(LOW HEAT
SPEED)
NO
YES
ROLLOUT
CIRCUIT
CLOSES
(MANUAL
RE−SET)
INDUCER ON
(HIGH SPEED)
ERROR
CODE
FLASHES
ROLLOUT
CIRCUITS
CLOSED?
CALL
FOR HEAT
ENDS?
DE−ENERGIZE
NO
NO
GAS VALVE
INDOOR BLOWER
ON (LOW HEAT
YES
SPEED)
YES
NO
INDUCER OFF
AFTER POST
PURGE
LOW
PRESSURE
SWITCH
OPEN?
ERROR CODE
FLASHES (AFTER
5 SECONDS)
INDOOR BLOWER
OFF AFTER HEAT
OFF DELAY
LOW PRESSURE
SWITCH OPENS
YES
YES
INDUCER ON
LOW SPEED
HARD LOCKOUT −
ERROR CODE
HIGH
2
FLASHES
PRESSURE
LOW
SWITCH
OPEN
BEFORE
INDUCER WAS
TURNED ON?
PRESSURE SWITCH
CLOSED WITHIN 120
SECONDS?
NO
LOW & HIGH
INDUCER TO
HIGH SPEED−
ERROR CODE
FLASHES
PRESSURE SWITCH
CLOSED WITHIN 30
SECONDS?
NO
YES
INDOOR
BLOWER
ON?
YES
YES
YES
NO
YES
PRE−PURGE
(15 SECONDS)
INDUCER OFF−
WAIT
NO
INDOOR
BLOWER
OFF AFTER
HEAT FAN
OFF DELAY
INTERPURGE
(15 SECONDS)
5 MINUTES
ERROR CODE
FLASHES
H.S.I. ON
(20 SECONDS)
1ST STAGE GAS
VALVE ENERGIZED
3
1
NO
IGNITION TRIAL
BEGINS (H.S.I. ON)
HEAT FAN ON DELAY
TIMER STARTED
GAS VALVE
FLAME
DE−ENERGIZED
5TH
WATCHGUARD −
POSTPURGE
(5 SECONDS)
INDUCER
OFF
SENSED WITHIN
4 SECONDS?
NO
UNSUCCESSFUL YES
TRIAL?
ERROR CODE
FLASHES
1
H.S.I. OFF
YES
H.S.I. OFF
1
WATCHGUARD LOCKOUT AUTOMATICALLY RESETS AFTER ONE HOUR
INDOOR
HARD LOCKOUT REQUIRES THERMOSTAT RESET OR CYCLING OF POWER TO RESET THE LOCKOUT.
2
3
BLOWER ON 45 SEC.
(LOW HEAT SPEED)
IN CASE HIGH SPEED INDUCER IS RUNNING AT THE TIME THE GAS VALVE GETS ENERGIZED,
2ND STAGE GAS VALVE IS ENERGIZED INSTEAD OF 1ST STAGE. 20 SECONDS AFTER FLAME
IS SENSED, INDUCER SWITCHES TO LOW SPEED, AND GAS VALVE SWITCHES TO 1ST STAGE.
2
CALL FOR HEAT SATISFIED
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Troubleshooting: Heating Sequence of Operation (Continued)
CALL FOR SECOND−STAGE HEAT
2
CALL FOR 2ND STAGE HEAT
1
(HIGH FIRE)
SINGLE STAGE
THERMOSTAT
2 STAGE THERMOSTAT
2
2ND STAGE
ON DELAY
EXPIRED?
RECOGNITION DELAY
(30 SECONDS)
EXPIRED?
ONLY FOR 1ST
REQUEST FOR
2ND STAGE HEAT
YES
YES
INDUCER SWITCHED
TO HIGH SPEED
HIGH
PRESSURE SWITCH
CLOSED WITHIN 10
SECONDS?
INDUCER SWITCHED
TO LOW SPEED
5 MINUTE DELAY
(ERROR CODE FLASHES)
NO
3
YES
2ND STAGE GAS VALVE
ENERGIZED
INDOOR BLOWER ENERGIZED
ON HIGH HEAT SPEED
3
CALL FOR HEAT SATISFIED
1
2
SYSTEM WILL ALWAYS LIGHT ON LOW FIIRE, EVEN IF 2ND STAGE HEAT IS IN PLACE.
WHEN USED WITH A SINGLE STAGE THERMOSTAT, SET SW1 TO THE ON POSITION IN DIP SWITCH S4.
3
IF THE HIGH FIRE PRESSURE SWITCH DOES NOT CLOSE WITHIN 5 ATTEMPTS, THE SYSTEM WILL OPERATE AT
LOW FIRE FOR THE REMAINDER OF THE CALL FOR HEAT REQUEST.
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Troubleshooting: Heating Sequence of Operation (Continued)
CALL FOR HEAT SATISFIED
FIRST−STAGE HEAT
SECOND−STAGE HEAT
2
3
RUN MODE:
1ST OR 2ND STAGE CALL FOR HEAT.
ALL INPUTS MONITORED (LIMIT, PRESSURE,
CALL FOR HEAT/COOL, FLAME LEVEL)
2ND STAGE HEAT
NO
2ND STAGE
CALL FOR HEAT
SATISFIED?
YES
DE−ENERGIZE 2ND STAGE
GAS VALVE
INDUCER SPEED SWITCHED
TO LOW SPEED
INDOOR BLOWER SWITCHED
TO LOW HEAT SPEED
1ST STAGE HEAT
NO
1ST STAGE
CALL FOR HEAT
SATISFIED?
YES
GAS VALVE
DE−ENERGIZED
INDUCER OFF AFTER
5 SECOND POST PURGE
INDOOR BLOWER OFF
AFTER FIELD SELECTABLE
OFF DELAY
1
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Troubleshooting: Cooling Sequence of Operation (Continued)
CALL FOR COOLING
1
1ST STAGE COOLING
REQUEST RECEIVED
1
WAIT FOR COMPRESSOR TIMED
OFF DELAY TO EXPIRE
ENERGIZE 1ST STAGE
COOLING CONTACTOR
(COMPRESSOR & FAN)
INDOOR BLOWER 2
SECOND ON DELAY
ENERGIZE INDOOR BLOWER
(LOW COOLING MODE)
2
MAINTAIN INDOOR
BLOWER
(LOW COOLING MODE)
YES
YES
1
1ST STAGE
COOLING REQUEST
STILL ACTIVE?
2ND STAGE
COOLING
NO
REQUEST?
YES
YES
ENERGIZE 2ND STAGE
COOLING CONTACTOR
(COMPRESSOR & FAN)
ENERGIZE INDOOR BLOWER
(HIGH COOLING MODE)
2
NO
2ND STAGE
COOLING REQUEST
STILL ACTIVE?
MAINTAIN INDOOR BLOWER
(HIGH COOLING MODE)
YES
NO
DE−ENERGIZE 2ND
STAGE COOLING
CONTACTOR
(COMPRESSOR & FAN)
1ST STAGE
COOLING REQUEST
STILL ACTIVE?
ENERGIZE AND MAINTAIN
INDOOR BLOWER AT
(LOW COOLING MODE)
YES
NO
DE−ENERGIZE 1ST
STAGE COOLING
CONTACTOR
1
2
CONTROL WILL NOT RESPOND TO A 2ND STAGE COOLING REQUEST UNLESS A 1ST STAGE
COOLING REQUEST IS ACTIVE.
(COMPRESSOR & FAN)
INDOOR BLOWER LOW COOLING MODE AND HIGH COOLING MODE HAVE SPECIFIC ON, OFF
AND SPEED RAMPING PROFILES. THE SPECIFIC PROFILE IS SELECTED USING THE
DIP SWITCHES ON THE CONROL.
DE−ENERGIZE INDOOR
2
BLOWER
1
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Troubleshooting: Continuous Fan Sequence of Operation
CALL FOR FAN
1
CALL FOR FAN
INDOOR BLOWER ON
CONTINUOUS FAN
SPEED
NO
CALL FOR FAN
REMOVED?
MAINTAIN INDOOR
BLOWER AT
CONTINUOUS FAN
YES
REQUEST
FOR COOLING
RECEIVED?
YES
MAINTAIN INDOOR
BLOWER AT
CONTINUOUS FAN
GO TO CALL FOR COOLING
4
NO
REQUEST
FOR HEAT
RECEIVED?
YES
INDOOR BLOWER OFF
1
GO TO CALL FOR 1ST STAGE HEAT
NO
DE−ENERGIZE INDOOR
BLOWER
1
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|