Lennox SLP98DFV SERIES User manual

Page 1
INSTALLATION
INSTRUCTIONS
SLP98DFV
507027-02
05/2016
Superseds 507027-01
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, personal
injury or loss of life. Installation and service must be
performed by a licensed professional HVAC installer or
equivalent, service agency, or the gas supplier.
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
This is a safety alert symbol and should never be
ignored. When you see this symbol on labels or in man-
uals, be alert to the potential for personal injury or death.
CAUTION
As with any mechanical equipment, contact with sharp
sheet metal edges can result in personal injury. Take
care while handling this equipment and wear gloves and
protective clothing.
NOTICE
A thermostat is not included and must be ordered
separately.
• The Lennox iComfort Wi-Fi®thermostat must be used
in communicating applications.
•In non-communicating applications, the Lennox
ComfortSense® 7500 thermostat may be used, as well
as other non-communicating thermostats.
In all cases, setup is critical to ensure proper system
operation.
Field wiring for both communicating and non-
communicating applications is illustrated in diagrams,
which begin on page 34.
© 2016 Lennox Industries Inc.
Dallas, Texas USA
DAVE LENNOX SIGNATURE®
COLLECTION GAS FURNACES
DOWNFLOW AIR DISCHARGE
Contents
Unit Dimensions - inches (mm) ......................................2
Parts Arrangement..........................................................3
SLP98DFV Gas Furnace................................................4
Shipping and Packing List ..............................................4
Safety Information ..........................................................4
Building Codes ...............................................................4
Use of Furnace as Construction Heater .........................5
General...........................................................................6
Installation - Setting Equipment......................................6
Filters..............................................................................9
Duct System ...................................................................9
Pipe & Fittings Specications .......................................10
Venting Options ............................................................12
Joint Cementing Procedure..........................................13
Venting Pracitces..........................................................14
Vent piping Guidliens....................................................14
Gas Piping....................................................................29
Electrical.......................................................................32
Integrated Control.........................................................40
Blower Data..................................................................44
Unit Start-Up.................................................................49
Turning Off Gas to Unit.................................................50
High Altitude Information ..............................................50
Gas Pressure Measurement.........................................50
Proper Combustion.......................................................50
Other Unit Adjustments.................................................53
Heating Sequence of Operation ...................................53
Service..........................................................................55
Repair Parts..................................................................56
Integrated Control Diagnostic Codes............................57
Conguring Unit Size Codes ........................................60
Troubleshooting: Heating Sequence of Operation .......61

Page 2
Unit Dimensions - inches (mm)
AIR
EXHAUST AIR
OUTLET
COMBUSTION
AIR INTAKE
FLOW
2-1/16 (52)
GAS PIPING INLET
(Either Side)
ELECTRICAL INLET
(Either Side)
RETURN AIR
OPENING
FRONT VIEW SIDE VIEW
TOP VIEW
A
B
C3/4
(19)
27-3/4
(705)
19-1/4
(489)
9-1/8 (232) Right
6-9/16 (167) Left
2 (51)
Either Side
33
(838)
3/4
(19)
B
Supply
Air
Supply
Air
9/16
(14)
9/16
(14)
9/16
(14)
9/16
(14)
19-7/16
(494)
3/4
(19)
CONDENSATE
TRAP CONNECTION
5
(127)
6-7/16 (163)
Either Side
9 (229)
Either Side
2-1/4
(57)
(Either Side)
1-1/2 (38)
Front Panel
Flue Condensate Trap Assembly
Furnished for external
field installation
on either side of unit.
(See installation instructions
for additional
information.)
7
(178)
Model A
in - mm
B
in - mm
C
in - mm
SLP98DF070V36B 17-1/2 - 446 16-3/8 - 416 16 - 406
SLP98DF090V36C
SLP98DF090V48C
SLP98DF090V60C
SLP98DF110V60C
21 - 553 19-7/8 - 505 19-1/2 - 495

Page 3
Parts Arrangement
BURNER BOX ASSEMBLY
GAS VALVE
ACCESS PANEL
COMBUSTION AIR INDUCER
BLOWER
ACCESS
PANEL
BLOWER ASSEMBLY
(Variable Speed Blower
Motor Is Hidden)
BAG ASSEMBLY
CONTROL BOX
(includes variable capacity
integrated control,
transformer, circuit breaker
and door switch)
PRIMARY LIMIT
SIDE VENT
PATCH PLATE
FIGURE 1

Page 4
SLP98DFV Gas Furnace
The SLP98DFV category IV gas furnace is equipped with
a variable-capacity, variable-speed integrated control.
This control ensures compatibility with the Lennox icom-
fort Wi-Fi® thermostat and Harmony III zone control sys-
tem, as well as a thermostat which provides humidity con-
trol. The furnace is equipped for installation in natural gas
applications only. A changeover kit may be ordered for LP
applications.
The SLP98DFV must be installed only as a Direct Vent
gas central furnace.
NOTE - In Direct Vent installations, combustion air is tak-
en from outdoors and ue gases are discharged outdoors.
See gure 2 for applications including roof termination.
DIRECT VENT INSTALLATION
EXHAUST OUTLET
COMBUSTION
A
IR INTAKE
OUTSIDE OF
HOUSE
FIGURE 2
Shipping and Packing List
Package 1 of 1 contains
1 - Assembled SLP98DFV unit
1 - Bag assembly containing the following:
1 - Snap bushing
1 - Snap plug
1 - Wire tie
1 - Condensate trap
1 - 3/4” Threaded street elbow
2 - 2” Street elbows
2 - Side vent sealing plates
2 - Side vent sealing gaskets
6 - Sheet metal screws
Check equipment for shipping damage. If you nd any
damage, immediately contact the last carrier.
The following items may also be ordered separately:
1 - Thermostat
1 - Natural to LP gas conversion kit
1 - High altitude kit
Safety Information
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, personal
injury or loss of life. Installation and service must be
performed by a licensed professional installer (or
equivalent), service agency or the gas supplier.
CAUTION
As with any mechanical equipment, contact with sharp
sheet metal edges can result in personal injury. Take
care while handling this equipment and wear gloves and
protective clothing.
Use only the type of gas approved for use with this fur-
nace. Refer to unit nameplate.
Building Codes
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/NFPA 54). The National Fuel
Gas Code is available from the following address:
American National Standards Institute, Inc.
11 West 42nd Street
New York, NY 10036
Installation Locations and Clearances
In Canada, installation must conform with current National
Standard of Canada CSA-B149 Natural Gas and Propane
Installation Codes, local plumbing or waste water codes
and other applicable local codes.
This furnace is designed for installation clearances to
combustible material as listed on the unit nameplate and
in the table in gure 7. Accessibility and service clearanc-
es must take precedence over re protection clearances.
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
oor. The furnace must be located or protected to avoid
physical damage by vehicles. When a furnace is installed
in a public garage, hangar, or other building that has a
hazardous atmosphere, the furnace must be installed ac-
cording to recommended good practice requirements and
current National Fuel Gas Code or CSA B149 standard.
NOTE - Furnace must be adjusted to obtain a temperature
rise (100% percent capacity) within the range(s) specied
on the unit nameplate. Failure to do so may cause erratic
limit operation and may also result in premature heat ex-
changer failure.
This SLP98DFV furnace must be installed so that its elec-
trical components are protected from water.

Page 5
Installed in Combination with a Cooling Coil
When this furnace is used with cooling units, it shall be in-
stalled in parallel with, or on the upstream side of, cooling
units to avoid condensation in the heating compartment.
With a parallel ow arrangement, a damper (or other
means to control the ow of air) must adequately prevent
chilled air from entering the furnace (gure 3). If the damp-
er is manually operated, it must be equipped to prevent
operation of either the heating or the cooling unit, unless it
is in the full HEAT or COOL setting.
AIR HANDLER
GAS UNIT
Dampers
(open
during cooling
operation only)
Dampers
(open during heating
operation only)
FURNACE INSTALLED PARALLEL
WITH COOLING COIL
FIGURE 3
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:
National Fire Protection Association
1 Battery March Park
Quincy, MA 02269
NOTE - This furnace is designed for a minimum continu-
ous return air temperature of 60°F (16°C) or an intermittent
operation down to 55°F (13°C) dry bulb for cases where a
night setback thermostat is used. Return air temperature
must not exceed 85°F (29°C) dry bulb.
In Canada, all electrical wiring and grounding for the unit
must be installed according to the current regulations of
the Canadian Electrical Code Part I (CSA Standard C22.1)
and/or local codes.
CAUTION
Do not set thermostat below 60F (16C) in heating mode.
Setting below 60F (16C) reduces the number of heating
cycles. Damage to the unit may occur that is not covered
by the warranty.
The SLP98DFV furnace may be installed in alcoves, clos-
ets, attics, basements, garages, and utility rooms.
This furnace is not designed for installation in mobile
homes, recreational vehicles, or outdoors.
Never use an open ame to test for gas leaks. Check all
connections using a commercially available soap solution
made specically for leak detection.
Use of Furnace as Construction Heater
Lennox does not recommend the use of SLP98DFV units
as a construction heater during any phase of construc-
tion. Very low return air temperatures, harmful vapors and
operation of the unit with clogged or misplaced lters will
damage the unit.
SLP98DFV units may be used for heating of buildings or
structures under construction, if the following conditions
are met:
• The vent system must be permanently installed per
these installation instructions.
• A room thermostat must control the furnace. The
use of xed jumpers that will provide continuous
heating is not allowed.
• The return air duct must be provided and sealed to
the furnace.
• Return air temperature range between 60°F (16°C)
and 80°F (27°C) must be maintained.
• Air lters must be installed in the system and must
be maintained during construction.
• Air lters must be replaced upon construction com-
pletion.
• The input rate and temperature rise must be set per
the furnace rating plate.
• One hundred percent (100%) outdoor air must be
provided for combustion air requirements during
construction. Temporary ducting may supply out-
door air to the furnace. Do not connect duct directly
to the furnace.
• The furnace heat exchanger, components, duct
system, air lters and evaporator coils must be
thoroughly cleaned following nal construction
clean-up.
• All furnace operating conditions (including ignition,
input rate, temperature rise and venting) must be
veried according to these installation instructions.

Page 6
General
WARNING
This prodcut contains a chemical known to the State
of California to cause cancer, birth defects, or other
reproductive harm.
CAUTION
SLP98DFV unit should not be installed in areas normally
subject to freezing temperatures.
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
In addition to the requirements outlined previously, the
following general recommendations must be considered
when installing a SLP98DFV furnace:
• Place the furnace as close to the center of the air
distribution system as possible. The furnace should
also be located close to the chimney or vent termi-
nation point.
• When the furnace is installed in an attic or other
insulated space, keep insulation away from the fur-
nace.
• When the furnace is installed in an unconditioned
space, consider provisions required to prevent
freezing of condensate drain system.
Installation - Setting Equipment
WARNING
Do not install the furnace on its front, back or in the
horizontal position. See gure 5. Do not connect the
return air ducts to the back of the furnace. Doing so
will adversely affect the operation of the safety control
devices, which could result in personal injury or death.
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,
condensate trap and drain connections, and installation
and service clearances [24 inches (610 mm) at unit front].
The unit must be level from side to side. Unit may be posi-
tioned from level to 1/2” toward the front to aid in draining.
See gure 4.
SETTING EQUIPMENT
FRONT VIEW SIDE VIEW
AIR FLOW AIR FLOW
1/2”
max.
AIR FLOW
SIDE VIEW
Unit must be level side-to-side. Unit may be positioned
from level to 1/2” toward the front to aid in draining.
FIGURE 4
Front
NOTE - Do not install the furnace on its front, back or in the horizontal position
Back Horizontal
FIGURE 5

Page 7
NOTE - The 1/2 hp blower motor used in the SLP98D-
F070V36B and SLP98DF090V36C unit is equipped
with three exible legs and one rigid leg. The rigid leg
is equipped with a shipping bolt and a at white plastic
washer (rather than the rubber mounting grommet used
with a exible 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
rigid leg will not touch the blower housing.
RIGID LEG
remove shipping bolt and washe
r
UNITS WITH 1/2 HP
BLOWER MOTOR
FIGURE 6
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or
alcove installations are shown in gure 7.
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 injury or death.
WARNING
Improper installation of the furnace can result in personal
injury or death. Combustion and ue products must
never be allowed to enter the return air system or air in
the living space. Use sheet metal screws and joint tape
to seal return air system to furnace.
In platform installations with furnace return, the furnace
should be sealed airtight to the return air plenum. 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. Allow absolutely no sagging,
cracks, gaps, etc. For no reason should return and
supply air duct systems ever be connected to or from
other heating devices such as a replace or stove, etc.
Fire, explosion, carbon monoxide poisoning, personal
injury and/or property damage could result.
IThe unit may be installed three ways in downow applica-
tions: on non-combustible ooring, on combustible oor-
ing using a base, or on a reverse-ow cooling coil cabinet.
Do not drag the unit across the oor in the downow
position. Floor and ange damage will result. Refer to
gure 7 for clearances in downow applications.
Downflow Application Installation Clearances
Top
Bottom
Left Side Right Side
Top 0
*Front 0
Back 0
Sides 0†
Vent 0
Floor NC‡
*Front clearance in alcove installation must be 24 in. (610 mm).
Maintain a minimum of 24 in. (610 mm) for front service access.
†Allow proper clearances to accommodate condensate trap and
vent pipe installation.
‡
tional base is installed between the furnace and the combustible
floor.
FIGURE 7
Installation on Non-Combustible Flooring (Figure 8)
1 - Cut oor opening keeping in mind clearances listed
on unit rating plate. Also keep in mind gas supply
connections, electrical supply, ue and air intake
connections and sufcient installation and servicing
clearances. See table 1 for correct oor opening
size.
2 - Flange warm air plenum and lower the plenum into
the opening.
3 - Set the unit over the plenum and seal the plenum
to the unit.
Ensure that the seal is adequate.

Page 8
TABLE 1
NON-COMBUSTIBLE FLOOR OPENINGSIZE
Cabinet Width Front to Rear Side to Side
in mm in mm
B Cabinet 17 - 1/2” 19 - 3/4 502 16 - 5/8 422
C Cabinet 21” 19 - 3/4 502 20 - 1/8 511
NOTE - Floor opening dimensions listed are 1/4 inch (6 mm) larger than
the unit opening. See dimension drawing on page 2.
SUPPLY AIR
PLENUM
PROPERLY
SIZED FLOOR
OPENING
FURNACE
FIGURE 8
Installation on Combustible Flooring (Figure 9)
1 - When unit is installed on a combustible oor,
a downow combustible ooring base must be
installed between the furnace and the oor. The
base must be ordered separately. See table 2 for
opening size to cut in oor.
CAUTION
The furnace and combustible ooring base shall not be
installed directly on carpeting, tile, or other combustible
material other than wood ooring.
TABLE 2
COMBUSTIBLE FLOORING BASE OPENING SIZE
Cabinet
Width
Catalog
Number
Front to Rear Side to Side
in mm in mm
B Cabinet
17 - 1/2”
11M60 22 559 18 - 3/4 476
C Cabinet
21”
11M61 22 559 22 - 3/4 578
FURNACE
SUPPLY AIR
PLENUM
COMBUSTIBLE
FLOORING BASE
PROPERLY
SIZED FLOOR
OPENING
FIGURE 9
2 - After opening is cut, set combustible ooring base
into opening.
3 - Check berglass strips on combustible ooring
base to make sure they are properly glued and
positioned.
4 - Lower supply air plenum into combustible ooring
base until plenum anges seal against berglass
strips.
NOTE - Be careful not to damage berglass strips. Check
for a tight seal.
5 - Set the furnace over the plenum.
6 - Ensure that the seal between the furnace and
plenum is adequate.
Installation on Cooling Coil Cabinet (Figure 10)
NOTE - Downow combustible ooring base is not used.
1 - Refer to reverse-ow coil installation instructions for
correctly sized opening in oor and installation of
cabinet.
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.
3 - Seal the cabinet and check for air leaks.

Page 9
COOLING COIL
PLENUM
PROPERLY
SIZED FLOOR
OPENING
FURNACE
FIGURE 10
Return Air Opening -- Downow Units
Return air may be brought in only through the top opening
of a furnace installed in the downow position. The follow-
ing steps should be taken when installing plenum:
1 - Bottom edge of plenum should be anged with a
hemmed edge (See gure 11 or 12).
2 - Sealing strips should be used to ensure an airtight
seal between the cabinet and the plenum.
3 - In all cases, plenum should be secured to top of
furnace using sheet metal screws.
4 - Make certain that an adequate seal is made.
SECURE FROM
OUTSIDE CABINET
PLENUM
(Field Provided)
SEALING STRIP
(Field Provided)
Side View
CABINET
SIDE PANEL
FIGURE 11
SECURE FROM
INSIDE CABINET
PLENUM
(Field Provided)
SEALING STRIP
(Field Provided)
Side View
CABINET
SIDE PANEL
FIGURE 12
Filters
This unit is not equipped with a lter or rack. A eld-provid-
ed lter is required for the unit to operate properly. Table 3
lists recommended lter size.
A lter must be in place whenever the unit is operating.
IMPORTANT
If a highefciency lter is being installed as part of this
system to ensure better indoor air quality, the lter must
be properly sized. Highefciency lters have a higher
static pressure drop than standardefciency glass/foam
lters. If the pressure drop is too great, system capacity
and performance may be reduced. The pressure drop
may also cause the limit to trip more frequently during
the winter and the indoor coil to freeze in the summer,
resulting in an increase in the number of service calls.
Before using any lter with this system, check the
specications provided by the lter manufacturer against
the data given in the appropriate Lennox Product
Specications bulletin. Additional information is provided
in Service and Application Note ACC002 (August 2000).
TABLE 3
Furnace Cabinet Width Fillter Size
B Cabinet 17-1/2” 16 X 25 X 1 (1)
C Cabinet 21-1/2”
Duct System
Use industry-approved standards 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.
NOTE - Operation of this furnace in heating mode (indoor
blower operating at selected heating speed) with an ex-
ternal static pressure which exceeds 0.8 inches w.c. may
result in erratic limit operation.
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 replace) is installed. When return air is drawn
from a room, a negative pressure is created in the room. If
a gas appliance is operating in a room with negative pres-
sure, the ue products can be pulled back down the vent
pipe and into the room. This reverse ow of the ue 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 system.
Use berglass sealing strips, caulking, or equivalent seal-
ing method between the plenum and the furnace cabinet
to ensure a tight seal. If a lter is installed, size the return
air duct to t the lter frame.

Page 10
Pipe & Fittings Specications
All pipe, ttings, primer and solvent cement must conform
with American National Standard Institute and the Ameri-
can Society for Testing and Materials (ANSI/ASTM) stan-
dards. The solvent shall be free-owing and contain no
lumps, undissolved particles or any foreign matter that
adversely affects the joint strength or chemical resistance
of the cement. The cement shall show no gelation, strati-
cation, or separation that cannot be removed by stirring.
Refer to table 4 for approved piping and tting materials.
TABLE 4
PIPING AND FITTINGS SPECIFICATIONS
Schedule 40 PVC (Pipe) D1785
Schedule 40 PVC (Cellular Core Pipe) F891
Schedule 40 PVC (Fittings) D2466
Schedule 40 CPVC (Pipe) F441
Schedule 40 CPVC (Fittings) F438
SDR-21 PVC or SDR-26 PVC (Pipe) D2241
SDR-21 CPVC or SDR-26 CPVC (Pipe) F442
Schedule 40 ABS Cellular Core DWV
(Pipe) F628
Schedule 40 ABS (Pipe) D1527
Schedule 40 ABS (Fittings) D2468
ABS-DWV (Drain Waste & Vent) (Pipe &
Fittings) D2661
PVC-DWV (Drain Waste & Vent) Pipe &
Fittings) D2665
PRIMER & SOLVENT CEMENT ASTM
SPECIFICATION
PVC & CPVC Primer F656
PVC Solvent Cement D2564
CPVC Solvent Cement F493
ABS Solvent Cement D2235
PVC/CPVC/ABS All Purpose Cement
For Fittings & Pipe of the same material
D2564, D2235,
F493
ABS to PVC or CPVC Transition Solvent
Cement D3188
CANADA PIPE & FITTING & SOLVENT
CEMENT MARKING
PVC & CPVC Pipe and Fittings
ULCS636
PVC & CPVC Solvent Cement
ABS to PVC or CPVC Transition
Cement
POLYPROPYLENE VENTING SYSTEM
PolyPro® by Duravent
InnoFlue® by Centrotherm
CAUTION
Solvent cements for plastic pipe are ammable liquids
and should be kept away from all sources of ignition.
Do not use excessive amounts of solvent cement when
making joints. Good ventilation should be maintained to
reduce re hazard and to minimize breathing of solvent
vapors. Avoid contact of cement with skin and eyes.
IMPORTANT
SLP98DFV exhaust and intake connections are made
of PVC. Use PVC primer and solvent cement when
using PVC vent pipe. When using ABS vent pipe, use
transitional solvent cement to make connections to the
PVC ttings in the unit.
Use PVC primer and solvent cement or ABS solvent ce-
ment meeting ASTM specications, refer to Table 4. As an
alternate, use all purpose cement, to bond ABS, PVC, or
CPVC pipe when using ttings and pipe made of the same
materials. Use transition solvent cement when bonding
ABS to either PVC or CPVC.
Low temperature solvent cement is recommended. Metal
or plastic strapping may be used for vent pipe hangers.
Uniformly apply a liberal coat of PVC primer for PVC.
Canadian Applications Only - Pipe, ttings, primer and
solvent cement used to vent (exhaust) this appliance must
be certied to ULC S636 and supplied by a single manu-
facturer as part of an approved vent (exhaust) system. In
addition, the rst three feet of vent pipe from the furnace
ue collar must be accessible for inspection.
Table 5 lists the available exhaust termination kits.