Lennox SLP98UHV SERIES Installation Instructions Manual

INSTALLATION
INSTRUCTIONS
SLP98UHV
E 2015 Lennox Industries Inc.
Dallas, Texas, USA
DAVE LENNOX SIGNATURE®
COLLECTION GAS FURNACE
UPFLOW / HORIZONTAL AIR DISCHARGE
507026-01
05/2015
Supersedes 01/2015
Litho U.S.A.
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
This 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.
CAUTION
As with any mechanical equipment, personal injury
can result from contact with sharp sheet metal
edges. Be careful when you handle this equipment.
AIR FLOW
UPFLOW
A thermostat is not included and must be ordered
separately.
AIR FLOW
AIR FLOW
NOTICE
HORIZONTAL LEFT
The Lennox icomfort Wi-Fi® thermostat must be
used in communicating applications.
HORIZONTAL RIGHT
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 HVAC in­
staller (or equivalent), service agency or the gas sup­
plier.
In non-communicating applications, the Lennox
ComfortSense® 7000 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-com­
municating applications is illustrated in diagrams,
which begin on Page 32.
Table of Contents
Unit Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shipping and Packing List . . . . . . . . . . . . . . . . . . . . . . . .
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use of Furnace as a Construction Heater . . . . . . . . . . .
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Duct System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pipe and Fittings Specifications . . . . . . . . . . . . . . . . . . .
Joint Cementing Procedure . . . . . . . . . . . . . . . . . . . . . . .
Venting Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vent Piping Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
3
4
4
4
5
6
6
10
11
11
12
13
13
27
Page 1
Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Integrated Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Motor Performance . . . . . . . . . . . . . . . . . . . . . . .
Unit Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Pressure Measurement . . . . . . . . . . . . . . . . . . . . . .
High Altitude Information . . . . . . . . . . . . . . . . . . . . . . . . .
Proper Combustion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other Unit Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . .
Heating Sequence of Operation . . . . . . . . . . . . . . . . . . .
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Integrated Control Diagnostic Codes . . . . . . . . . . . . . . .
Configuring Unit Size Codes . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
38
42
47
48
50
50
50
51
53
54
55
58
59
Unit Dimensions - inches (mm)
NOTE − 60C and 60D size units that require second stage
air volumes over 1800 cfm (850 L/s) must have one
of the following:
1. Single side return air with transition, to accommodate
20 x 25 x 1 in. (508 x 635 x 25 mm) cleanable air
filter. Required to maintain proper air velocity.
2. Single side return air with optional return air base
3. Bottom return air.
4. Return air from both sides.
5. Bottom and one side return air
See blower performance tables for more information.
2
Optional External Side Return Air Filter Kit is not for use
with the optional RAB Return Air Base.
EXHAUST AIR
OUTLET
3−1/4
(83)
1
1−7/8 (48)
D
SUPPLY AIR
OPENING
COMBUSTION
AIR INTAKE
2
OPTIONAL
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side)
23−3/4
(603)
25
(635)
TOP VIEW
B
27−3/4
(705)
1−1/2 (38)
Front Panel
A
6−9/16 (167)
Left
9 (229)
Right
12−5/8 (321)
(Either Side)
2 OPTIONAL
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side)
33
(838)
2 (51)
(Either Side)
GAS PIPING INLET
(Either Side)
CONDENSATE
TRAP CONNECTION
(Either Side)
6−1/2 (165)
(Either Side)
ELECTRICAL
INLET
(Either Side)
Return
Air Opening
(Either Side)
AIR FLOW
1 Bottom
Return
Air Opening
1−15/16 (49)
3/4
(19)
5/8
(16)
3−1/4
(83)
23−1/2
(597)
1 Bottom Return
Air Opening
FRONT VIEW
SLP98UH Model No.
14
(356)
1 Side
16
(406)
C
1−1/2
(38)
23
(584)
14−3/4
(375)
3/4
(19)
9/16
(14)
19−7/16
(494)
9/16 (14)
SIDE VIEW
A
B
C
D
in.
mm
in.
mm
in.
mm
in.
mm
070XV36B
090XV36C
090XV48C
090XV60C
110XV60C
17−1/2
446
16−3/8
416
16
406
7−5/8
194
21
533
19−7/8
505
19−1/2
495
9−3/8
238
135XV60D
24−1/2
622
23−3/8
594
23
584
11−1/8
283
Page 2
Parts Arrangement
BURNER BOX ASSEMBLY
PRESSURE SWITCHES
HEAT EXCHANGER
VARIABLE
CAPACITY
GAS VALVE
PRIMARY LIMIT
VARIABLE SPEED
COMBUSTION AIR
INDUCER
BAG ASSEMBLIES
(shipping location)
COLD END HEADER
BOX
ACCESS PANEL
VARIABLE SPEED BLOWER MOTOR
SIGHT GLASS
SHIPPING BLOCK
(-135 UNITS ONLY)
INNER BLOWER
ACCESS PANEL
CONTROL BOX
(includes variable capacity integrated control
transformer, circuit breaker and door switch)
FIGURE 1
Page 3
SLP98UHV Gas Furnace
The SLP98UHV category IV gas furnace is equipped with a
variable-capacity, variable-speed integrated control. This
control ensures compatibility with the Lennox icomfort WiFi® thermostat, the Harmony IIIt zone control system, or a
thermostat which provides humidity control. Each
SLP98UHV is shipped ready for installation in the upflow,
horizontal left air discharge or horizontal right air discharge
position.
The furnace is equipped for installation in natural gas ap­
plications only. A changeover kit may be ordered for LP ap­
plications.
The SLP98UHV must be installed only as a Direct Vent
gas furnace.
NOTE - In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors.
See figure 2 for applications including roof termination.
DIRECT VENT INSTALLATION
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.
Safety Information
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.
EXHAUST OUTLET
COMBUSTION
AIR INTAKE
OUTSIDE OF
HOUSE
CAUTION
As with any mechanical equipment, personal injury
can result from contact with sharp sheet metal
edges. Be careful when you handle this equipment.
FIGURE 2
Shipping and Packing List
Package 1 of 1 contains
1 - Assembled SLP98UHV unit
1 - Bag assembly containing the following:
1 - Snap bushing
1 - Snap plug
1 - Wire tie
1 - Condensate trap
1 - Condensate trap cap
1 - Condensate trap cap clamp
1 - 3/4” Threaded street elbow
Check equipment for shipping damage. If you find 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
1 - Horizontal suspension kit
Use only the type of gas approved for use with this furnace.
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
Installed Locations
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 com­
bustible material as listed on the unit nameplate and in the
tables in figures 10 and 11. Accessibility and service clear­
ances must take precedence over fire protection clear­
ances.
NOTE - For installation on combustible floors, the furnace
shall not be installed directly on carpeting, tile, or other
combustible material other than wood flooring.
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 a public
Page 4
garage, hangar, or other building that has a hazardous at­
mosphere, the furnace must be installed according to rec­
ommended good practice requirements and current Na­
tional Fuel Gas Code or CSA B149 standard.
NOTE - NOTE - Furnace must be adjusted to obtain a tem­
perature rise (100% percent capacity) 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 SLP98UHV furnace must be installed so that its elec­
trical components are protected from water.
Installed in Combination with a Cooling Coil
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
chilled air from entering the furnace. If the damper is manu­
ally 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. See figure 3.
NOTE - This furnace is designed for a minimum continuous
return air temperature of 60°F (16°C) or an intermittent op­
eration 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 60°F (16°C) in heating
mode. Setting thermostat below 60°F (16°C) reduces
the number of heating cycles. Damage to the unit
may occur that is not covered by the warranty.
The SLP98UHV 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 flame to test for gas leaks. Check all
connections using a commercially available soap solution
made specifically for leak detection.
Use of Furnace as Construction Heater
Heating Unit Installed Parallel to Air Handler Unit
Dampers
(open during heating operation only)
Gas Unit
Air Handler Unit
Dampers
(open during cooling operation only)
Heating Unit Installed Upstream of Cooling Unit
Gas Unit
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 Electric
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
Page 5
Lennox does not recommend the use of SLP98UHV 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.
SLP98UHV 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.
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.
D Air filters must be replaced upon construction comple­
tion.
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.
D The furnace heat exchanger, components, duct sys­
tem, 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.
General
Installation - Setting Equipment
WARNING
WARNING
The State of California has determined that this prod­
uct may contain or produce a chemical or chemicals,
in very low doses, which may cause serious illness
or death. It may also cause cancer, birth defects or
reproductive harm.
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.
WARNING
Do not install the furnace on its front or back.
See figure 4.
CAUTION
SLP98UHV unit should not be installed in areas nor­
mally 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 fol­
lowing general recommendations must be considered
when installing a SLP98UHV furnace:
• 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.
• When the furnace is installed in an attic or other insu­
lated space, keep insulation away from the furnace.
• When the furnace is installed in an unconditioned
space, consider provisions required to prevent freezing
of condensate drain system.
• Please consult the manufacturer of your evaporator coil
for their recommendations on distance required
between the heat exchanger and their drain pan. Ad­
equate space must be provided between the drain pan
and the furnace heat exchanger.
Front
Back
FIGURE 4
Upflow Applications
The SLP98UHV gas furnace can be installed as shipped in
the upflow position. Refer to figure 10 for clearances.
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 figure 5.
Page 6
SETTING EQUIPMENT
Unit must be level side-to-side. Unit may be positioned from level to 1/2” toward the front to aid in draining.
UPFLOW APPLICATION
UNIT
FRONT
UNIT
FRONT
AIR FLOW
1/2” max.
SIDE VIEW
SIDE VIEW
FRONT VIEW
AIR FLOW
HORIZONTAL APPLICATION
UNIT
FRONT
FRONT VIEW
END VIEW
1/2”
max.
FIGURE 5
Removing the Bottom Panel
Side Return Air
(with transition and filter)
1−1/2”
Remove the two screws that secure the bottom cap to the
furnace. Pivot the bottom cap down to release the bottom
panel. Once the bottom panel has been removed, reinstall
the bottom cap. See figure 7.
20” X 25” X 1”
(508mmX635mmX 25mm)
Air Filter
Removing the Bottom Panel
Return
Air
Plenum
Transition
Screw
FIGURE 6
SLP98UHV applications which include side return air
and a condensate trap installed on the same side of the
cabinet (trap can be installed remotely within 5 feet) re­
quire either a return air base or field-fabricated transi­
tion to accommodate an optional IAQ accessory taller
than 14.5”. See figure 6.
Page 7
Bottom Cap
Bottom Panel
FIGURE 7
Optional Return Air Base
(Upflow Applications Only)
CONDENSATE
TRAP
FURNACE
FRONT
INDOOR AIR
QUALITY
CABINET
(PCO, Filter
Cabinet, etc.)
AIR FLOW
17−1/2 (446) B Width (50W98)
21 (533) C Width (50W99)
24−1/2 (622) D Width (51W00)
IF BASE
IS USED
WITHOUT
IAQ CABINET,
A SINGLE
RETURN AIR
PLENUM
MUST
COVER BOTH
UNIT AND
RETURN
AIR BASE
OPENINGS
3−1/4
(83)
7−1/4
(184)
1 23
(584)
Overall
(Maximum)
1
Minimum
11 (279)
2 Maximum
1 Unit side return air
14 (356)
Opening
5−5/8
(143)
(570)
Overall
(Maximum)
SIDE RETURN
AIR OPENINGS
(Either Side)
23
(584)
26−7/8
(683)
OPTIONAL
RETURN
AIR BASE
1 22−7/16
3/4
(19)
SIDE VIEW
FRONT VIEW
NOTE- Optional side return air filter kits are not for use with return air base.
1 Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet.
Minimum unit side return air opening dimensions for units requiring 1800 cfm or more of air (W x H): 23 x 11 in. (584 x 279 mm).
The opening can be cut as needed to accommodate plenum or IAQ cabinet while maintaining dimensions shown.
Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return air
opening. The size of the opening must not extend beyond the markings on the furnace cabinet.
2 To minimize pressure drop, the largest opening height possible (up to 14 inches) is preferred.
FIGURE 8
NOTE - Units with 1/2 hp blower motor are equipped with
three flexible legs and one rigid leg. The rigid leg is
equipped with a shipping bolt and a flat white plastic wash­
er (rather than the rubber mounting grommet used with a
flexible mounting leg). See figure 9. The bolt and washer
must be removed before the furnace is placed into op­
eration. After the bolt and washer have been removed, the
rigid leg will not touch the blower housing.
WARNING
Blower access panel must be securely in place when
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
SLP98UHV070V36B and
SL98UH090V036C WITH 1/2 HP
BLOWER MOTOR
RIGID LEG
remove shipping bolt and washer
FIGURE 9
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or al­
cove installations are shown in figures 10 and 11.
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 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 fur­
nace 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.
For no reason should return and supply air duct sys­
tems ever be connected to or from other heating de­
vices such as a fireplace or stove, etc. Fire, explo­
sion, carbon monoxide poisoning, personal injury
and/or property damage could result.
Page 8
Horizontal Application
Installation Clearances
Installation Clearances
Top
Right-Hand Discharge
Left End
Right Side
Left Side
Right End
Air
Flow
Air
Flow
Bottom (Floor)**
Left-Hand Discharge
Bottom (Floor)
Top/Plenum
1 in. (25 mm)
*Front
0
Back
0
Sides
0†
Vent
0
Floor
0‡
Top
Left End
Right End
Air
Flow
Air
Flow
Bottom (Floor)**
*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.
‡For installations on a combustible floor, do not install the fur­
nace directly on carpeting, tile or other combustible materials oth­
er than wood flooring.
FIGURE 10
Return Air -- Upflow Units
Return air can be brought in through the bottom or either
side of the furnace installed in an upflow application. If the
furnace is installed on a platform with bottom return, make
an airtight seal between the bottom of the furnace and the
platform to ensure that the furnace operates properly and
safely. The furnace is equipped with a removable bottom
panel to facilitate installation.
Markings are provided on both sides of the furnace cabinet
for installations that require side return air. Cut the furnace
cabinet at the maximum dimensions shown on page 2.
Refer to Engineering Handbook for additional information.
Setting an Upflow Unit
When the side return air inlets are used in an upflow ap­
plication, it may be necessary to install shims on the bottom
of the furnace.
Horizontal Applications
The SLP98UHV furnace can be installed in horizontal ap­
plications with either right- or left-hand air discharge.
Refer to figure 11 for clearances in horizontal applications.
Page 9
Top
0
Front*
0
Back
0
Ends
0
Vent
0
Floor
0‡
*Front clearance in alcove installation must be 24 in. (610 mm).
Maintain a minimum of 24 in. (610 mm) for front service access.
**An 8“ service clearance must be maintained below the unit to
provide for servicing of the condensate trap.
‡For installations on a combustible floor, do not install the fur­
nace directly on carpeting, tile or other combustible materials oth­
er than wood flooring.
FIGURE 11
Suspended Installation of Horizontal Unit
This furnace may be installed in either an attic or a crawl­
space. Either suspend the furnace from roof rafters or floor
joists, as shown in figure 12, or install the furnace on a plat­
form, as shown in figure 13. A horizontal suspension kit
(51W10) may be ordered from Lennox or use equivalent.
NOTE - Heavy-gauge sheet metal straps may be used to
suspend the unit from roof rafters or ceiling joists. When
straps are used to suspend the unit in this way, support
must be provided for both the ends. The straps must not in­
terfere with the plenum or exhaust piping installation. Cool­
ing coils and supply and return air plenums must be
supported separately.
NOTE - When the furnace is installed on a platform in a
crawlspace, it must be elevated enough to avoid water
damage and to allow the evaporator coil to drain.
INTAKE PIPE
HORIZONTAL SUSPENSION KIT
EXHAUST PIPE
Internal Brace
(provided with kit)
Metal Strap
(typical)
*GAS CONNECTION
*Gas connector may be
used for Canadian
installation if accept­
able by local authority
having jurisdiction.
Bracket
(typical)
Air
Flow
RAISED
PLATFORM
SERVICE PLATFORM
FIGURE 12
Platform Installation of Horizontal Unit
1 - Select location for unit keeping in mind service and
other necessary clearances. See figure 11.
2 - Construct a raised wooden frame and cover frame
with a plywood sheet. If unit is installed above finished
space, fabricate an auxiliary drain pan to be installed
under unit. Set unit in drain pan as shown in figure 13.
Leave 8 inches for service clearance below unit for
condensate trap.
3 - Provide a service platform in front of unit. When instal­
ling the unit in a crawl space, a proper support platform
may be created using cement blocks.
4 - Route auxiliary drain line so that water draining from
this outlet will be easily noticed by the homeowner.
5 - If necessary, run the condensate line into a conden­
sate pump to meet drain line slope requirements. The
pump must be rated for use with condensing furnaces.
Protect the condensate discharge line from the pump
to the outside to avoid freezing.
6 - Continue with exhaust, condensate and intake piping
installation according to instructions.
FIGURE 13
Return Air -- Horizontal Applications
Return air must be brought in through the end of a furnace
installed in the horizontal position. The furnace is equipped
with a removable bottom panel to facilitate installation. See
figure 7.
Filters
This unit is not equipped with a filter or rack. A field-pro­
vided filter is required for the unit to operate properly. Table
1 lists recommended filter sizes.
IMPORTANT
If a high­efficiency filter is being installed as part of
this system to ensure better indoor air quality, the fil­
ter must be properly sized. High­efficiency filters
have a higher static pressure drop than standard­ef­
ficiency glass/foam filters. If the pressure drop is too
great, system capacity and performance may be re­
duced. 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 filter with this system, check the
specifications provided by the filter manufacturer
against the data given in the appropriate Lennox
Product Specifications bulletin. Additional informa­
tion is provided in Service and Application Note
ACC­00­2 (August 2000).
A filter must be in place when the unit is operating.
NOTE - In upflow applications where side return air fil­
ter is installed on same side as the condensate trap,
make sure that clearance is maintained to ensure fu­
ture access to the filter access panel.
TABLE 1
Furnace
Cabinet Width
Page 10
Filter Size
Side Return
Bottom Return
17-1/2”
16 X 25 X 1 (1)
16 X 25 X 1 (1)
21”
16 X 25 X 1 (1)
20 X 25 X 1 (1)
24-1/2”
16 X 25 X 1 (2)
24 X 25 X 1 (1)
TABLE 2
PIPING AND FITTINGS SPECIFICATIONS
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 exter­
nal static pressure which exceeds 0.8 inches w.c. may re­
sult in erratic limit operation.
Schedule 40 PVC (Pipe)
Schedule 40 PVC (Cellular Core Pipe)
D1785
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)
Supply Air Plenum
F628
Schedule 40 ABS (Pipe)
D1527
Schedule 40 ABS (Fittings)
D2468
If the furnace is installed without a cooling coil, a removable
access panel should be installed in the supply air duct. The
access panel should be large enough to permit inspection
(by reflected light) of the heat exchanger for leaks after the
furnace is installed. If present, this access panel must al­
ways be in place when the furnace is operating and it must
not allow leaks into the supply air duct system.
ABS-DWV (Drain Waste & Vent)
(Pipe & Fittings)
D2661
PVC-DWV (Drain Waste & Vent)
Pipe & Fittings)
D2665
Return Air Plenum
CPVC Solvent Cement
ASTM
SPECIFICATION
PRIMER & SOLVENT CEMENT
PVC & CPVC Primer
PVC Solvent Cement
F656
D2564
F493
ABS Solvent Cement
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 a room, 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 distrib­
uted throughout the house by the furnace duct system.
PVC/CPVC/ABS All Purpose Cement For
Fittings & Pipe of the same material
D2564, D2235, F493
ABS to PVC or CPVC Transition Solvent
Cement
D3138
CANADA PIPE & FITTING & SOLVENT
CEMENT
PVC & CPVC Pipe and Fittings
PVC & CPVC Solvent Cement
MARKING
ULCS636
ABS to PVC or CPVC Transition Cement
POLYPROPYLENE VENTING SYSTEM
PolyPro by Duravent
ULC-S636
CAUTION
Return air can be brought in through the bottom or either
side of the furnace (return air brought in through either side
of the furnace allowed in upflow applications only). If a fur­
nace with bottom return air is installed on a platform, make
an airtight seal between the bottom of the furnace and the
platform to ensure that the unit operates properly and safe­
ly. Use fiberglass sealing strips, caulking, or equivalent
sealing method between the plenum and the furnace cabi­
net to ensure a tight seal. If a filter is installed, size the re­
turn air duct to fit the filter frame.
Solvent cements for plastic pipe are flammable liq­
uids 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 fire hazard and to minimize
breathing of solvent vapors. Avoid contact of ce­
ment with skin and eyes.
IMPORTANT
SLP98UHV 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 con­
nections to the PVC fittings in the unit.
Pipe & Fittings Specifications
All pipe, fittings, 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-flowing and contain no
lumps, undissolved particles or any foreign matter that ad­
versely affects the joint strength or chemical resistance of
the cement. The cement shall show no gelation, stratifica­
tion, or separation that cannot be removed by stirring. Re­
fer to table 2 for approved piping and fitting materials.
D2235
Use PVC primer and solvent cement or ABS solvent ce­
ment meeting ASTM specifications, refer to Table 2. As an
alternate, use all purpose cement, to bond ABS, PVC, or
CPVC pipe when using fittings and pipe made of the same
materials. Use transition solvent cement when bonding
ABS to either PVC or CPVC.
Page 11
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
TABLE 3
OUTDOOR TERMINATION USAGE*
STANDARD
Input Size
045
070
090
110
135
Vent
Pipe
Dia. in.
Flush­
Mount
Kit
CONCENTRIC
Wall Kit
Wall Ring Kit
2 inch
1-1/2 inch
2 inch
71M80
(US)
444W92
(CA)
69M29
(US)
444W92
(CA)
3 inch
2 inch
3 inch
51W11
(US)
51W12
(CA)
22G44 (US)
430G28 (CA)
44J40
(US)
481J20 (CA)
15F74
2
3YES
YES
1YES
1YES
5YES
2YES
2-1/2
3YES
YES
1YES
1YES
5YES
2YES
3
3YES
YES
1YES
1YES
5YES
2YES
2
3YES
YES
1YES
1YES
5YES
2YES
2-1/2
3YES
YES
1YES
1YES
5YES
2YES
3
3YES
YES
1YES
1YES
5YES
2YES
2
3YES
YES
YES
5YES
YES
YES
2-1/2
3YES
YES
YES
5YES
YES
YES
3
3YES
YES
YES
5YES
YES
YES
2
YES
YES
YES
5YES
YES
YES
2-1/2
YES
YES
5YES
YES
YES
3
YES
YES
5YES
YES
YES
3
YES
YES
5YES
Field
Fabricated
60L46 (US)
(CA)
444W93
YES
NOTE - Standard Terminations do not include any vent pipe or elbows external to the structure. Any vent pipe or elbows external to the structure must be included in total vent length
calculations. See vent length tables.
* Kits must be properly installed according to kit instructions.
1Requires field-provided outdoor 1-1/2” exhaust accelerator.
2Concentric kits 71M80 and 44W92 include 1-1/2” outdoor accelerator, when used with 045 and 070 input models.
3 Flush mount kits 51W11 and 51W12 includes 1-1/2 in. outdoor exhaust accelerator, required when used with 045, 070 and 090 input models.
4 Termination kits 30G28, 44W92, 4493 and 81J20 are certified to ULC S636 for use in Canada only.
5 See table 7 for vent accelerator requirements.
Joint Cementing Procedure
All cementing of joints should be done according to the
specifications outlined in ASTM D 2855.
NOTE - A sheet metal screw may be used to secure the in­
take pipe to the connector, if desired. Use a drill or self tap­
ping screw to make a pilot hole.
DANGER
DANGER OF EXPLOSION!
Fumes from PVC glue may ignite during system
check. Allow fumes to dissipate for at least 5 minutes
before placing unit into operation.
1 - Measure and cut vent pipe to desired length.
2 - Debur and chamfer end of pipe, removing any ridges
or rough edges. If end is not chamfered, edge of pipe
may remove cement from fitting socket and result in a
leaking joint.
NOTE - Check the inside of vent pipe thoroughly for
any obstruction that may alter furnace operation.
3 - Clean and dry surfaces to be joined.
4 - Test fit joint and mark depth of fitting on outside of
pipe.
5 - Uniformly apply a liberal coat of PVC primer for PVC or
use a clean dry cloth for ABS to clean inside socket
surface of fitting and male end of pipe to depth of fitting
socket.
Page 12
6 - Promptly apply solvent cement to end of pipe and in­
side socket surface of fitting. Cement should be ap­
plied lightly but uniformly to inside of socket. Take care
to keep excess cement out of socket. Apply second
coat to end of pipe.
NOTE - Time is critical at this stage. Do not allow prim­
er to dry before applying cement.
7 - Immediately after applying last coat of cement to pipe,
and while both inside socket surface and end of pipe
are wet with cement, forcefully insert end of pipe into
socket until it bottoms out. Turn PVC pipe 1/4 turn dur­
ing assembly (but not after pipe is fully inserted) to dis­
tribute cement evenly. DO NOT turn ABS or cellular
core pipe.
NOTE - Assembly should be completed within 20 sec­
onds after last application of cement. Hammer blows
should not be used when inserting pipe.
8 - After assembly, wipe excess cement from pipe at end
of fitting socket. A properly made joint will show a bead
around its entire perimeter. Any gaps may indicate a
defective assembly due to insufficient solvent.
9 - Handle joints carefully until completely set.
Exhaust Piping (Figures 18 and 19)
3 - Route piping to outside of structure. Continue with
installation following instructions given in piping ter­
mination section.
Intake Piping (Figures 18 and 19)
The SLP98UHV furnace may be installed only in direct
vent applications.
The SLP98UHV is designed for combustion air intake
through an inlet in the unit's top cap. Intake air piping is in­
dependent of exhaust piping.
REPLACING FURNACE THAT WAS PART OF A
COMMON VENT SYSTEM
CHIMNEY
OR GAS
VENT
(Check sizing
for water
heater only)
WATER
HEATER
FURNACE
(Replaced
by SLP98)
Venting Practices
OPENINGS
(To Adjacent
Room)
Piping Suspension Guidelines
SCHEDULE 40 PVC -Support every 5 feet.
All other pipe* -Support every 3 feet.
If an SLP98UHV furnace replaces a furnace which was
commonly vented with another gas appliance, the size
of the existing vent pipe for that gas appliance must be
checked. Without the heat of the original furnace flue
products, the existing vent pipe is probably oversized for
the single water heater or other appliance. The vent
should be checked for proper draw with the remaining
appliance.
* See table2 for allowable pipe.
NOTE - Isolate piping at the point where it exits the outside wall or
roof in order to prevent transmission of vibration to the structure.
Wall Thickness Guidelines
FIGURE 15
24” maximum
3/4” minimum
inside
Wall
CAUTION
Do not discharge exhaust into an existing stack or
stack that also serves another gas appliance. If verti­
cal discharge through an existing unused stack is re­
quired, insert PVC pipe inside the stack until the end
is even with the top or outlet end of the metal stack.
outside
CAUTION
FIGURE 14
1 - In areas where piping penetrates joists or interior
walls, hole must be large enou`gh to allow clearance
on all sides of pipe through center of hole using a
hanger.
2 - When furnace is installed in a residence where unit is
shut down for an extended period of time, such as a
vacation home, make provisions for draining conden­
sate collection trap and lines.
The exhaust vent pipe operates under positive pres­
sure and must be completely sealed to prevent leak­
age of combustion products into the living space.
Vent Piping Guidelines
NOTE - Lennox has approved the use of DuraVent ® manu­
factured vent pipe and terminations as an option to PVC.
When using the PolyPro ® by DuraVent venting system the
vent pipe requirements stated in the unit installation in­
struction – minimum & maximum vent lengths, termination
Page 13
clearances, etc. – apply and must be followed. Follow the
instructions provided with PoyPro by DuraVent venting
system for assembly or if requirements are more restrict­
ive. The PolyPro by Duravent venting system must also fol­
low the uninsulated and unconditioned space criteria listed
in table 6.
IMPORTANT
Do not use screens or perforated metal in exhaust or
intake terminations. Doing so will cause freeze-ups
and may block the terminations.
Piping Size Process
The SLP98UHV is installed only as a Direct Vent gas
central furnace.
NOTE - In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors.
Intake and exhaust pipe sizing -- Size pipe according to
tables 4 and 5. Count all elbows inside and outside the
home. Table 4 lists the minimum vent pipe lengths per­
mitted. Table 5 lists the maximum pipe lengths permitted.
Regardless of the diameter of pipe used, the standard roof
and wall terminations described in section Exhaust Piping
Terminations should be used. Exhaust vent termination
pipe is sized to optimize the velocity of the exhaust gas as it
exits the termination. Refer to table 7.
In some applications which permit the use of several differ­
ent sizes of vent pipe, a combination vent pipe may be
used. Contact Lennox' Application Department for assis­
tance in sizing vent pipe in these applications.
Use the steps in figure 17 to correctly size vent pipe diame­
ter.
NOTE - It is acceptable to use any pipe size which fits within
the guidelines allowed in table 5.
1
2
3
Which style termination
being used?
Standard or concentric?
See table 3.
Which needs
most elbows?
Intake or
exhaust?
How many elbows?
4 Count all elbows inside
and outside house.
Exhaust Pipe
Exhaust Pipe
Horizontal
Gas Furnace
What is the
furnace capacity?
045, 070, 090,
110 or 135?
5
Desired pipe size?
2”, 2-1/2”, 3”
12” Min .
12” ma x
of straight pip e
NOTE - All horizontal runs of exhaust pipe must slope back to­
ward unit. A minimum of 1/4” (6mm) drop for each 12” (305mm)
of horizontal run is mandatory for drainage.
6
What is the altitude of
the furnace installation?
7
Use table 5 or 6 to find
max intake or exhaust pipe
length. Includes all vent
pipe and elbows inside
and outside the house.
NOTE - Exhaust pipe MUST be glued to furnace exhaust fittings.
NOTE - Exhaust piping should be checked carefully to make
sure there are no sags or low spots.
FIGURE 17
FIGURE 16
NOTE - The exhaust collar on all models is sized to accom­
modate 2” Schedule 40 vent pipe. In horizontal applica­
tions, any transition to exhaust pipe larger than 2” must be
made in vertical runs of the pipe. Therefore a 2” elbow must
be added before the pipe is transitioned to any size larger
than 2”. This elbow must be added to the elbow count used
to determine acceptable vent lengths. Contact the Applica­
tion Department for more information concerning sizing of
vent systems which include multiple pipe sizes.
TABLE 4
MINIMUM VENT PIPE LENGTHS
SLP98UHV
MODEL
MIN. EQUIV.
VENT
LENGTH
EXAMPLE
15 ft.*
5 ft. plus 2 elbows of 2”, 2-1/2”
or 3” diameter pipe
5 ft. plus 2 elbows of 3”
diameter pipe
070, 090, 110
135
*Any approved termination may be added to the minimum equivalent
length listed.
Page 14
TABLE 5
Maximum Allowable Intake or Exhaust Vent Length in Feet
*Size intake and exhaust pipe length separately. Values in table are for Intake OR Exhaust, not combined total. Both Intake and Exhaust must be same pipe
size.
NOTE - Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length calculation.
Number Of
90° Elbows
Used
1
2
3
4
5
6
7
8
9
10
Number Of
90° Elbows
Used
1
2
3
4
5
6
7
8
9
10
Number Of
90° Ebows
Used
1
2
3
4
5
6
7
8
9
10
Number Of
90° Elbows
Used
1
2
3
4
5
6
7
8
9
10
070
66
61
56
51
46
41
36
31
26
21
Standard Termination at Elevation 0 - 7500'
2-1/2” Pipe
Model
135
070
090
110
135
140
93
43
135
88
38
130
83
33
125
78
28
120
73
23
n/a
n/a
115
68
18
110
63
13
105
58
100
53
n/a
95
48
Standard Termination at Elevation 7501' - 10,000'
2” Pipe
2-1/2” Pipe
Model
Model
090
110
135
070
090
110
135
44
115
68
39
110
63
34
105
58
29
100
53
24
95
48
n/a
n/a
n/a
n/a
19
90
43
14
85
38
80
33
75
28
n/a
70
23
070
83
78
73
68
63
58
53
48
43
38
2” Pipe
Mode
090
110
67
12
62
7
57
52
47
42
n/a
37
32
27
22
070
91
86
81
76
71
66
61
56
51
46
070
58
53
48
43
38
33
28
23
18
13
2” Pipe
Model
090
110
69
14
64
9
59
54
49
44
n/a
39
34
29
24
Concentric Termination at Elevation 0 - 7500'
2-1/2” Pipe
Model
135
070
090
110
135
130
89
39
125
84
34
120
79
29
115
74
24
110
69
19
n/a
n/a
105
64
14
100
59
95
54
n/a
90
49
85
44
Concentric Termination at Elevation 7501' - 10,000'
2” Pipe
2-1/2” Pipe
Model
Model
090
110
135
070
090
110
135
42
105
64
37
100
59
32
95
54
27
90
49
22
85
44
n/a
n/a
n/a
n/a
17
80
39
12
75
34
70
29
65
24
n/a
60
19
Page 15
070
162
157
152
147
142
137
132
127
122
117
3” Pipe
Model
090
110
143
118
138
113
133
108
128
103
123
98
118
93
113
88
108
83
103
78
98
73
135
114
109
104
99
94
89
84
79
74
69
070
137
132
127
122
117
112
107
102
97
92
3” Pipe
Model
090
110
118
93
113
88
108
83
103
78
98
73
93
68
88
63
83
58
78
53
73
48
135
89
84
79
74
69
64
59
54
49
44
070
146
141
136
131
126
121
116
111
106
101
3” Pipe
Model
090
110
139
114
134
109
129
104
124
99
119
94
114
89
109
84
104
79
99
74
94
69
135
105
100
95
90
85
80
75
70
65
60
070
121
116
111
106
101
96
91
86
81
76
3” Pipe
Model
090
110
114
89
109
84
104
79
99
74
94
69
89
64
84
59
79
54
74
49
69
44
135
80
75
70
65
60
55
50
45
40
35
TYPICAL EXHAUST AND INTAKE PIPE CONNECTIONS IN UPFLOW APPLICATIONS
Intake
Exhaust
Exhaust
2”
2”
2”
Intake
or
2”
2”
2”
*2”
*2”
DO NOT transition
from smaller to larger
pipe size in horizontal
runs of exhaust pipe.
* When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible.
FIGURE 18
TYPICAL EXHAUST AND INTAKE PIPE CONNECTIONS IN HORIZONTAL AIR APPLICATIONS
(RIGHT HAND DISCHARGE SHOWN)
12” max.
Exhaust
2”
45°
MAX
or
2”
2”
2”
2”
45°
MAX
2”
or
2”
2”
Intake
SIDE VIEW
3”
3”
Exhaust
*2”
TRANSITION
*2”
*2”
*2”
DO NOT transition
from smaller to larger
pipe size in horizontal
runs of exhaust pipe.
Intake
* When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible.
FIGURE 19
Page 16
VENT TERMINATION CLEARANCES
FOR DIRECT VENT INSTALLATIONS IN THE USA AND CANADA
INSIDE CORNER
DETAIL
G
H
A
D
E
B
L
Fixed
Closed
Operable
F
B
B
C
I
Fixed
Closed
Operable
M
B
K
J
A
B
AREA WHERE TERMINAL
IS NOT PERMITTED
AIR SUPPLY INLET
VENT TERMINAL
US Installations1
A=
Clearance above grade, veranda,
porch, deck or balcony
B=
Clearance to window or
door that may be opened
C=
Clearance to permanently
closed window
D=
Vertical clearance to ventilated soffit
located above the terminal within a
horizontal distance of 2 feet (610mm)
from the center line of the terminal
E=
Clearance to unventilated soffit
F=
Clearance to outside corner
G=
Clearance to inside corner
H=
Clearance to each side of center line ex­
tended above meter / regulator assembly
I=
Clearance to service regulator
vent outlet
Clearance to non-mechanical air
supply inlet to building or the com­
bustion air inlet to any other ap­
pliance
J=
K=
L=
Clearance to mechanical air sup­
ply inlet
Clearance above paved sidewalk or
paved driveway located on public property
12 inches (305mm) or 12 in. (305mm)
above average snow accumulation.
Canadian Installations2
12 inches (305mm) or 12 in. (305mm)
above average snow accumulation.
6 inches (152mm) for appliances <10,000 6 inches (152mm) for appliances <10,000
Btuh (3kw), 9 inches (228mm) for ap­
Btuh (3kw), 12 inches (305mm) for
pliances > 10,000 Btuh (3kw) and <50,000
appliances > 10,000 Btuh (3kw) and
Btuh (15 kw), 12 inches (305mm) for ap­
<100,000 Btuh (30kw), 36 inches (.9m)
pliances > 50,000 Btuh (15kw)
for appliances > 100,000 Btuh (30kw)
* 12”
* 12”
* Equal to or greater than soffit depth
* Equal to or greater than soffit depth
* No minimum to outside corner
*
* Equal to or greater than soffit depth
* Equal to or greater than soffit depth
* No minimum to outside corner
*
3 feet (.9m) within a height 15 feet (4.5m)
above the meter / regulator assembly
3 feet (.9m) within a height 15 feet (4.5m)
above the meter / regulator assembly
3 feet (.9m)
* 3 feet (.9m)
6 inches (152mm) for appliances <10,000 6 inches (152mm) for appliances <10,000
Btuh (3kw), 9 inches (228mm) for ap­
Btuh (3kw), 12 inches (305mm) for
pliances > 10,000 Btuh (3kw) and <50,000
appliances > 10,000 Btuh (3kw) and
Btuh (15 kw), 12 inches (305mm) for ap­
<100,000 Btuh (30kw), 36 inches (.9m)
pliances > 50,000 Btuh (15kw)
for appliances > 100,000 Btuh (30kw)
3 feet (.9m) above if within 10 feet
6 feet (1.8m)
(3m) horizontally
7 feet (2.1m)†
* 7 feet (2.1m)
M = Clearance under veranda, porch, deck or balcony
*12 inches (305mm)‡
1 In
accordance with the current ANSI Z223.1/NFPA 54 Natural Fuel Gas Code
2 In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code
† A vent shall not terminate directly above a sidewalk or paved driveway that is located
between two single family dwellings and serves both dwellings.
‡ Permitted only if veranda, porch, deck or balcony is fully open on a minimum of
two sides beneath the floor. Lennox recommends avoiding this location if possible.
FIGURE 20
Page 17
12 inches (305mm)‡
*For clearances not specified in ANSI Z223.1/NFPA 54 or CSA
B149.1, clearance will be in accordance with local installation
codes and the requirements of the gas supplier and these
installation instructions.”
General Guidelines for Vent Terminations
In Direct Vent applications, combustion air is taken from
outdoors and the flue gases are discharged to the out­
doors. The SLP98UHV is classified as a direct vent, Cate­
gory IV gas furnace.
In Direct Vent applications, the vent termination is limited
by local building codes. In the absence of local codes, refer
to the current National Fuel Gas Code ANSI Z223-1/NFPA
54 in U.S.A., and current CSA-B149 Natural Gas and Pro­
pane Installation Codes in Canada for details.
Position termination according to location given in figure
20. In addition, position termination so it is free from any ob­
structions and 12” above the average snow accumulation.
At vent termination, care must be taken to maintain
protective coatings over building materials (prolonged
exposure to exhaust condensate can destroy protective
coatings). It is recommended that the exhaust outlet not be
located within 6 feet (1.8m) of an outdoor AC unit because
the condensate can damage the painted coating.
NOTE - See table 6 for maximum allowed exhaust pipe
length without insulation in unconditioned space during
winter design temperatures below 32°F (0°C). If required
exhaust pipe should be insulated with 1/2” (13mm) Arma­
flex or equivalent. In extreme cold climate areas, 3/4”
(19mm) Armaflex or equivalent may be necessary. Insula­
tion must be protected from deterioration. Armaflex with
UV protection is permissable. Basements or other en­
closed areas that are not exposed to the outdoor ambient
temperature and are above 32 degrees F (0°C) are to be
considered conditioned spaces.
IMPORTANT
Do not use screens or perforated metal in exhaust
terminations. Doing so will cause freeze-ups and
may block the terminations.
IMPORTANT
For Canadian Installations Only:
In accordance to CSA International B149 installation
codes, the minimum allowed distance between the
combustion air intake inlet and the exhaust outlet of
other appliances shall not be less than 12 inches
(305mm).
Page 18
TABLE 6
Maximum Allowable Vent Pipe Length (in ft.) Without Insulation In Unconditioned Space For
Winter Design Temperatures Modulating High Efficiency Furnace
Winter Design
Temperatures1 °F (°C)
Unit Input Size
Vent Pipe
Diameter
070
090
PVC
2PP
110
PVC
2PP
135
PVC
2PP
PVC
2PP
32 to 21
2 in.
8
8
14
13
16
15
N/A
N/A
(0 to -6)
2-1/2 in.
6
N/A
9
N/A
12
N/A
N/A
N/A
3 in.
4
3
6
5
8
7
12
11
2 in
5
5
7
6
8
7
N/A
N/A
2-1/2 in.
4
N/A
5
N/A
6
N/A
N/A
N/A
3 in.
2
2
2
2
4
3
6
5
2 in.
3
3
4
4
5
4
N/A
N/A
2-1/2 in.
2
N/A
2
N/A
3
N/A
N/A
N/A
3 in.
1
1
1
1
1
1
2
1
20 to 1
(-7 to -17)
0 to -20
(-18 to -29)
1Refer
to 99% Minimum Design Temperature table provided in the current edition of the ASHRAE Fundamentals Handbook.
vent pipe (PP)
NOTE - Maximum uninsulated vent lengths listed may include the termination(vent pipe exterior to the structure) and cannot exceed 5 linear feet or the
maximum allowable intake or exhaust vent length listed in table 5 or which ever is less.
NOTE - If insulation is required in an unconditioned space, it must be located on the pipe closest to the furnace. See figure21.
2 Poly-Propylene
Conditioned
Space
Pipe Insulation
Conditioned
Space
Unconditioned
Space
FIGURE 21
Page 19
Exhaust
Pipe
Intake
Pipe
Details of Intake and Exhaust Piping Terminations for
Direct Vent Installations
NOTE - In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged to outdoors.
NOTE - Flue gas may be slightly acidic and may adversely
affect some building materials. If any vent termination is
used and the flue gasses may impinge on the building ma­
terial, a corrosion-resistant shield (minimum 24 inches
square) should be used to protect the wall surface. If the
optional tee is used, the protective shield is recommended.
The shield should be constructed using wood, plastic,
sheet metal or other suitable material. All seams, joints,
cracks, etc. in the affected area should be sealed using an
appropriate sealant. See figure 29.
Intake and exhaust pipes may be routed either horizontally
through an outside wall or vertically through the roof. In at­
tic or closet installations, vertical termination through the
roof is preferred. Figures 22 through 30 show typical ter­
minations.
1 - Intake and exhaust terminations are not required to be
in the same pressure zone. You may exit the intake on
one side of the structure and the exhaust on another
side (figure 23). You may exit the exhaust out the roof
and the intake out the side of the structure (figure 24).
2 - Intake and exhaust pipes should be placed as close
together as possible at termination end (refer to il­
lustrations). Maximum separation is 3” (76mm) on roof
terminations and 6” (152mm) on side wall termina­
tions.
NOTE - When venting in different pressure zones, the
maximum separation requirement of intake and ex­
haust pipe DOES NOT apply.
3 - On roof terminations, the intake piping should termi­
nate straight down using two 90° elbows (See figure
22).
4 - Exhaust piping must terminate straight out or up as
shown. A reducer may be required on the exhaust pip­
ing at the point where it exits the structure to improve
the velocity of exhaust away from the intake piping.
See table 7.
NOTE - Care must be taken to avoid recirculation of
exhaust back into intake pipe.
Inches(mm)
3”(76mm) MAX.
SIZE TERMINATION
PIPE PER TABLE 7.
UNCONDITIONED
ATTIC SPACE
8” (203mm) MIN
12” (305mm) ABOVE
AVERAGE SNOW
ACCUMULATION
3” (76mm) OR
2” (51mm) PVC
PROVIDE SUPPORT
FOR INTAKE AND
EXHAUST LINES
DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
FIGURE 22
Exiting Exhaust and Intake Vent
(different pressure zone)
Exhaust
Pipe
Inlet Air
(Minimum 12 in.
305 MM) above
grade or snow
accumulation
Furnace
FIGURE 23
Exiting Exhaust and Intake Vent
(different pressure zone)
Roof Terminated
Exhaust Pipe
5 - On field-supplied terminations for side wall exit, ex­
haust piping may extend a maximum of 12 inches
(305mm) for 2” PVC and 20 inches (508mm) for 3”
(76mm) PVC beyond the outside wall. Intake piping
should be as short as possible. See figure 29.
6 - On field-supplied terminations, a minimum distance
between the end of the exhaust pipe and the end of the
intake pipe without a termination elbow is 8” and a
minimum distance of 6” with a termination elbow. See
figure 29.
Furnace
Inlet Air
(Minimum 12 in.
305 MM) above
grade or snow
accumulation
FIGURE 24
TABLE 7
EXHAUST PIPE TERMINATION SIZE REDUCTION
SLP98UHV
MODEL
Termination Pipe Size
*070
*090
110
135
1-1/2”
2”
2”
2”
*SLP98UH-070 and -090 units with the flush-mount termination must use
the 1-1/2”accelerator supplied with the kit.
Page 20
7 - If intake and exhaust piping must be run up a side wall
to position above snow accumulation or other ob­
structions, piping must be supported. At least one
bracket must be used within 6” from the top of the el­
bow and then every 24” (610mm) as shown in figure
29, to prevent any movement in any direction. When
exhaust and intake piping must be run up an outside
wall, the exhaust piping must be terminated with pipe
sized per table 7.The intake piping may be equipped
with a 90° elbow turndown. Using turndown will add 5
feet (1.5m) to the equivalent length of the pip
8 - Based on the recommendation of the manufacturer, a
multiple furnace installation may use a group of up to
four terminations assembled together horizontally, as
shown in figure 27.
1 1/2” (38mm) accelerator
provided with 71M80 &
44W92 kits for
SL98UH070V36B
12” (305mm)
INTAKE
Minimum
Above Average
Snow
Accumulation
12”
(305mm)
5-1/2”
(140mm)
5”
(127mm)
INTAKE
AIR
18” MAX.
(457mm)
Front View
EXHAUST VENT
12” (305mm) Min.
above grade or
average snow ac­
INTAKE
cumulation.
AIR
Inches (mm)
Side View
optional intake elbow
OPTIONAL VENT TERMINATION FOR MULTIPLE UNIT
INSTALLATION OF DIRECT VENT WALL TERMINATION KIT
(30G28 or 81J20)
FIGURE 27
2” EXTENSION FOR 2” PVC
PIPE1” EXTENSION FOR 3”
PVC PIPE
FLASHING
(Not Furnished)
FURNACE
EXHAUST
PIPE
4''
FURNACE
INTAKE
PIPE
SHEET METAL STRAP
(Clamp and sheet metal strap
must be field−installed to support
the weight of the termination kit.)
CLAMP
GLUE EXHAUST
END FLUSH INTO
TERMINATION
FIELD-PROVIDED
REDUCER MAY BE REQUIRED
TO ADAPT LARGER VENT
PIPE SIZE TO TERMINATION
FLAT
SIDE
FLUSH-MOUNT SIDE WALL TERMINATION KIT
51W11 (US) or 51W12 (Canada)
FIGURE 28
FIGURE 25
FIELD-PROVIDED
REDUCER MAY BE RE­
QUIRED TO ADAPT
LARGER VENT PIPE
SIZE TO TERMINATION.
1 1/2” (38mm) accelerator
provided on 71M80 &
44W92 kits for
SL98UHV-36B-070
OUTSIDE
WALL
EXHAUST
AIR
INTAKE
AIR
EXHAUST
AIR
CLAMP
(Not Furnished)
1-1/2” ACCELERATOR
(all -070 and -090 units)
DIRECT VENT CONCENTRIC ROOFTOP TERMINATION
71M80, 69M29 or 60L46 (US)
44W92 or 44W93 (Canada)
INTAKE
AIR
EXHAUST
VENT
12” (305mm) Min.
INTAKE above grade or
AIR average snow ac­
cumulation.
GRADE
DIRECT VENT CONCENTRIC WALL TERMINATION
71M80, 69M29 or 60L46 (US)
41W92 or 41W93 (Canada)
FIGURE 26
Page 21
FIELD FABRICATED WALL TERMINATION
NOTE − FIELD−PROVIDED
REDUCER MAY BE
REQUIRED TO ADAPT
LARGER VENT PIPE SIZE
TO TERMINATION
2” (51mm) 3” (76mm)
Vent Pipe Vent Pipe
D
D
B
C1
A
Intake
Elbow
B
C2
A
STRAIGHT
APPPLICATION
A− Minimum clearance
above grade or average
snow accumulation
12” (305 mm)
12” (305 mm)
B− Maximum horizontal
separation between
intake and exhaust
6” (152 mm)
6” (152 mm)
C1 -Minimum from end of
exhaust to inlet of intake 8” (203 mm)
8” (203 mm)
C2 -Minimum from end of
exhaust to inlet of intake 6” (152 mm)
6” (152 mm)
D− Maximum exhaust
pipe length
20” (508 mm)
12” (305 mm)
E− Maximum wall support
distance from top of each 6” (152 mm)
pipe (intake/exhaust)
* WALL
SUPPORT
D
E
D
E
B
B
A
C1
EXTENDED
APPLICATION
A
C2
6” (152 mm)
See venting table 5 for maximum venting lengths
with this arrangement.
* Use wall support every 24” (610 mm). Use two
wall supports if extension is greater than
24” (610 mm) but less than 48” (1219 mm).
NOTE − One wall support must be within 6” (152 mm)
from top of each pipe (intake and exhaust) to prevent
movement in any direction.
ALTERNATE TERMINATIONS (TEE & FORTY−FIVE DEGREE ELBOWS ONLY)
B
D
B
Exhaust
D
1
C
C
2
Intake
Elbow
A
3
1
E
Intake
B
B− Horizontal
separation between
intake and exhaust
C− Minimum from
end of exhaust to
inlet of intake
A
Front View of
Intake and Exhaust
D
A− Clearance above
grade or average snow
accumulation
D− Exhaust pipe length
2” (51MM)
Vent Pipe
3” (76MM)
Vent Pipe
12” (305 mm) Min.
12” (305 mm) Min.
6” (152 mm) Min.
6” (152 mm) Min.
24” (610 mm) Max. 24” (610 mm) Max.
9” (227 mm) Min.
9” (227 mm) Min.
12” (305 mm) Min. 12” (305 mm) Min.
16” (405 mm) Max. 20” (508 mm) Max.
E− Wall support distance
from top of each pipe
6” (152 mm) Max.
(intake/exhaust)
6” (152 mm) Max.
Exhaust
12”
C
2
A
1
The exhaust termination tee should be connected to the 2” or 3” PVC flue pipe as shown in the illustration.
Do not use an accelerator in applications that include an exhaust termination tee.
The accelerator is not required.
2 As required. Flue gas may be acidic and may adversely affect some building materials. If a side wall vent
termination is used and flue gases will impinge on the building materials, a corrosion−resistant shield
(24 inches square) should be used to protect the wall surface. If optional tee is used, the protective shield
is recommended. The shield should be constructed using wood, sheet metal or other suitable material.
All seams, joints, cracks, etc. in affected area, should be sealed using an appropriate sealant.
3 Exhaust pipe 45° elbow can be rotated to the side away from the combustion air inlet to direct exhaust
away from adjacent property. The exhaust must never be directed toward the combustion air inlet.
FIGURE 29
Page 22
SLP98 DIRECT VENT APPLICATION
STRAIGHT-CUT OR
USING EXISTING CHIMNEY
ANGLE-CUT IN DIRECTION
CONDENSATE TRAP AND PLUG LOCATIONS
(Unit shown in upflow position)
OF ROOF SLOPE *
3” - 8”
(76mm203mm)
8” - 12”
(203mm - 305mm)
1-1/2 in.
Minimum 12” (305MM)
above chimney top
plate or average snow
accumulation
INTAKE PIPE
INSULATION (optional)
SHOULDER OF FITTINGS
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
SHEET
METAL TOP
PLATE
INSULATE
TO FORM
SEAL
ALTERNATE
INTAKE PIPE
3” - 8”
(76mm203mm)
Plug
(same on left side)
EXTERIOR
PORTION OF
CHIMNEY
*SIZE TERMINATION
PIPE PER TABLE 7.
NOTE - Do not discharge exhaust gases directly into any chimney or vent stack. If ver­
tical discharge through an existing unused chimney or stack is required, insert piping
inside chimney until the pipe open end is above top of chimney and terminate as illus­
trated. In any exterior portion of chimney, the exhaust vent must be insulated.
FIGURE 30
Condensate Piping
This unit is designed for either right‐ or left‐side exit of con­
densate piping in upflow applications. In horizontal applica­
tions, the condensate trap must extend below the unit. An
8” service clearance is required for the condensate trap.
Refer to figures 31 and 33 for condensate trap locations.
Figure 39 shows trap assembly using 1/2” PVC or 3/4”
PVC.
NOTE - If necessary the condensate trap may be installed
up to 5’ away from the furnace. Use PVC pipe to connect
trap to furnace condensate outlet. Piping from furnace
must slope down a minimum of 1/4” per ft. toward trap.
1 - Determine which side condensate piping will exit the
unit, location of trap, field-provided fittings and length
of PVC pipe required to reach available drain.
2 - Use a large flat head screw driver or a 1/2” drive socket
extension and remove plug (figure 31) from the cold
end header box at the appropriate location on the side
of the unit. Install provided 3/4 NPT street elbow fitting
into cold end header box. Use Teflon tape or appropri­
ate pipe dope.
3 - Install the cap over the clean out opening at the base
of the trap. Secure with clamp. See figure 39.
4 - Install drain trap using appropriate PVC fittings, glue
all joints. Glue the provided drain trap as shown in fig­
ure 39. Route the condensate line to an open drain.
Condensate line must maintain a 1/4” downward slope
from the furnace to the drain.
Page 23
NOTE - In upflow applications where side return
air filter is installed on same side as the conden­
sate trap, filter rack must be installed beyond
condensate trap or trap must be re-located to
avoid interference.
FIGURE 31
5 - Figures 34 and 36 show the furnace and evaporator
coil using a separate drain. If necessary the conden­
sate line from the furnace and evaporator coil can
drain together. See figures 35, 37 and 38.
Upflow furnace (figure 37) - In upflow furnace applica­
tions the field provided vent must be a minimum 1” to a
maximum 2” length above the condensate drain outlet
connection. Any length above 2” may result in a
flooded heat exchanger if the combined primary drain
line were to become restricted.
Horizontal furnace (figure 38) - In horizontal furnace
applications the field provided vent must be a mini­
mum 4” to a maximum 5” length above the condensate
drain outlet connection. Any length above 5” may re­
sult in a flooded heat exchanger if the combined pri­
mary drain line were to become restricted.
NOTE - In horizontal applications it is recommended to
install a secondary drain pan underneath the unit and
trap assembly.
NOTE - Appropriately sized tubing and barbed fitting
may be used for condensate drain. Attach to the drain
on the trap using a hose clamp. See figure 32.
SLP98UHV With Evaporator
Coil Using A Separate Drain
Field Provided Drain Components
Evaporator drain
line required
(Trap at coil is optional)
Elbow
Field Provided Vent
(1” min. 2” max. above
condensate connection)
Barbed Fitting
Tubing
Hose Clamp
Condensate
Drain Connection
FIGURE 32
CAUTION
Do not use copper tubing or existing copper conden­
sate lines for drain line.
6 - If unit will be started immediately upon completion of
installation, prime trap per procedure outlined in Unit
Start-Up section.
Condensate line must slope downward away from the
trap to drain. If drain level is above condensate trap,
condensate pump must be used. Condensate drain
line should be routed within the conditioned space to
avoid freezing of condensate and blockage of drain
line. If this is not possible, a heat cable kit may be used
on the condensate trap and line. Heating cable kit is
available from Lennox in various lengths; 6 ft. (1.8m) kit no. 26K68 and 24 ft. (7.3m) - kit no. 26K69.
CONDENSATE TRAP LOCATIONS
FIGURE 34
Condensate Trap With Optional Overflow Switch
(Unit shown in upflow position with remote trap)
From Evaporator Coil
HorizontalFurnace4” Min. to 5” Max.above
condensatedrain connection)
Field ProvidedVent
Min. 1” Above Condensate
Drain Connection
1” Min.
2” Max.
FurnaceCondensate
DrainConnection
*5’ max.
PVC PipeOnly
Optional
Trap Can Be Installed a
Maximum 5’ From Furnace
To Drain
*Piping from furnace must slope down a
minimum 1/4” per ft. toward trap
FIGURE 35
FIGURE 33
Page 24
SLP98UHV with Evaporator Coil Using a Separate Drain
(Unit shown in horizontal left-hand discharge position)
Field Provided Vent
(4” min. to 5” max. above
condensate connection)
Evaporator
Coil
4”min
5”max
5’ max.
PVC Pipe Only
Condensate
Drain Connection
Drain Pan
(Trap at coil is optional)
Piping from furnace and evaporator coil must slope down a minimum 1/4” per ft. toward trap
.
FIGURE 36
SLP98UHV with Evaporator
Coil Using a Common Drain
IMPORTANT
When combining the furnace and evaporator
coil drains together, the A/C condensate drain
outlet must be vented to relieve pressure in or­
der for the furnace pressure switch to operate
properly.
Evaporator drain
line required
(Trap at coil is optional)
(1” min. to 2” Max.above
condensatedrain connection)
Condensate
Drain Connection
FIGURE 37
SLP98UHV with Evaporator Coil Using a Common Drain
(Unit shown in horizontal left−hand discharge position)
(4” min. to 5” Max.above
condensatedrain connection)
Evaporator
Coil
4”min
5”max
5’ max.
PVC Pipe Only
Condensate Drain
Connection
Drain Pan
(Trap at coil is optional)
Piping from furnace and evaporator coil must slope
down a minimum 1/4” per ft. toward trap
FIGURE 38
Page 25
TRAP / DRAIN ASSEMBLY USING 1/2” PVC OR 3/4” PVC
Optional Condensate Drain Connection
Adapter 3/4 inch slip X
3/4 inch mpt (not furnished)
90° Street Elbow
3/4 inch PVC
(not furnished)
Adapter 3/4 inch slip X
3/4 inch mpt (not furnished)
Condensate Drain
Connection In Unit
90° Street Elbow
3/4 inch PVC
( furnished)
1 (25 mm) Min.
2 (50 mm) Max.
Above Top Of
Condensate Drain
Connection In Unit
Vent
Condensate Drain
Connection In Unit
5 Feet
Maximum
90° Elbow 3/4 inch PVC
(Not Furnished)
To
Trap
Optional DrainPiping FromTrap
3/4 inch PVC Pipe
(Not Furnished)
1/2 inch PVC Pipe
(Not Furnished)
Coupling 3/4 inch slip X slip
(Not Furnished)
Drain Assembly for 1/2 inch Drain Pipe
1/2 inch PVC Pipe
(Not Furnished)
Drain Trap
Assembly
(Furnished)
90° Elbow
1/2 inch PVC
(Not Furnished)
To
Drain
Drain Assembly for 3/4 inch Drain Pipe
Drain Trap
Clean Out
90° Elbow
3/4 inch PVC
(Not Furnished)
90° Elbow
3/4 inch PVC
(Not Furnished)
To Coupling 3/4 inch slip X slip
Drain
(Not Furnished)
To
Drain
DrainTrap Assembly with 1/2 inch Piping
1 (25 mm) Min. 2 (50 mm) Max. Above Top
Of Condensate Drain Connection In Unit
DrainTrap Assembly
(Furnished)
7
(178)
Vent
DrainTrap Assembly with 3/4 inch Piping
1 (25 mm) Min. 2 (50 mm) Max. Above Top
Of Condensate Drain Connection In Unit
Vent
3/4 inch
1/2 inch
Condensate Drain
Connection In Unit
Condensate Drain
Connection In Unit
To
Drain
To
Drain
FIGURE 39
Page 26
Gas Piping
IMPORTANT
CAUTION
Compounds used on threaded joints of gas piping
must be resistant to the actions of liquified petro­
leum gases.
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.
MANUAL MAIN SHUT-OFF
VALVE WILL NOT HOLD
NORMAL TEST PRESSURE
WARNING
CAP
1/8” N.P.T. PLUGGED TA­
P
FURNACE
ISOLATE
GAS VALVE
Do not exceed 600 in-lbs (50 ft.-lbs) torque when at­
taching the gas piping to the gas valve.
1 - Gas piping may be routed into the unit through either
the left‐ or right‐hand side in upflow applications, and
either the top or bottom in horizontal applications.
Supply piping enters into the gas valve from the side of
the valve as shown in figures 41 and 42.
2 - When connecting gas supply, factors such as length of
run, number of fittings and furnace rating must be con­
sidered to avoid excessive pressure drop. Table 8 lists
recommended pipe sizes for typical applications.
NOTE - Use two wrenches when connecting gas pip­
ing to avoid transferring torque to the manifold.
3 - Gas piping must not run in or through air ducts, clothes
chutes, chimneys or gas vents, dumb waiters or eleva­
tor shafts. Center gas line through piping hole. Gas
line should not touch side of unit. See figures 41 and
42.
4 - Piping should be sloped 1/4 inch per 15 feet (6mm per
5.6m) upward toward the gas meter from the furnace.
The piping must be supported at proper intervals, ev­
ery 8 to 10 feet (2.44 to 3.05m), using suitable hangers
or straps. Install a drip leg in vertical pipe runs to serve
as a trap for sediment or condensate.
5 - A 1/8” N.P.T. plugged tap or pressure post is located
on the gas valve to facilitate test gauge connection.
See figures 48.
6 - In some localities, codes may require installation of a
manual main shut‐off valve and union (furnished by in­
staller) external to the unit. Union must be of the
ground joint type.
FIGURE 40
Leak Check
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.
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 pressures less
than or equal to 1/2 psig (3.48 kPa, 14 inches w.c.).
Page 27
IMPORTANT
When testing gas lines using pressures in excess of
1/2 psig (3.48 kPa), gas valve must be disconnected
and isolated. See figure 40. Gas valves can be dam­
aged if subjected to pressures greater than 1/2 psig
(3.48 kPa).
WARNING
FIRE OR EXPLOSION HAZARD
Failure to follow the safety warnings exactly could
result in serious injury, death, or property damage.
Never use an open flame to test for gas leaks. Check
all connections using a commercially available soap
solution made specifically for leak detection. Some
soaps used for leak detection are corrosive to cer­
tain metals. Carefully rinse piping thoroughly after
leak test has been completed.
Upflow Application
Left Side Piping
(Standard)
Upflow Application
Right Side Piping
(Alternate)
1/2” NPT
1/2” NPT
MANUAL
MAIN SHUT-OFF
VALVE
MANUAL
MAIN SHUT-OFF
VALVE
GROUND
JOINT
UNION
GROUND
JOINT
UNION
DRIP LEG
DRIP LEG
FIELD
PROVIDED
AND INSTALLED
NOTE - BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET
FIGURE 41
Horizontal Applications
Possible Gas Piping Configurations
MANUAL
MAIN SHUT-OFF
VALVE
MANUAL
MAIN SHUT-OFF
VALVE
Horizontal Application
Left-Side Air Discharge
GROUND
JOINT
UNION
GROUND
JOINT
UNION
DRIP LEG
DRIP LEG
Horizontal Application
Right-Side Air Discharge
MANUAL
MAIN SHUT-OFF
VALVE
FIELD
PROVIDED
AND INSTALLED
NOTE - BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET
FIGURE 42
Page 28
GROUND
JOINT
UNION
DRIP LEG
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 - Follow the lighting instructions. Turn on the appliance
that is being inspected. Adjust the thermostat so that
the appliance operates continuously.
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.
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.
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.
Removal of the Furnace from Common Vent
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 prop­
erly vent the remaining attached appliances.
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 vent­
ing system has been installed improperly, you must
correct the system as indicated in the general venting re­
quirements section.
WARNING
CARBON MONOXIDE POISONING HAZARD
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:
1 - Seal any unused openings in the common venting sys­
tem.
2 - Inspect the venting system for proper size and horizon­
tal pitch. Determine that there is no blockage, restric­
tion, leakage, corrosion, or other deficiencies which
could cause an unsafe condition.
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.
TABLE 8
GAS PIPE CAPACITY - FT3/HR (kL/HR)
Nominal
Iron Pipe
Size
inches
(mm)
1/2
(12.7)
Internal
Diameter
inches
(mm)
10
(3.048)
20
(6.096)
30
(9.144)
40
(12.192)
50
(15.240)
60
(18.288)
70
(21.336)
80
(24.384)
90
(27.432)
100
(30.480)
.622
(17.799)
172
(4.87)
118
(3.34)
95
(2.69)
81
(2.29)
72
(2.03)
65
(1.84)
60
(1.69)
56
(1.58)
52
(1.47)
50
(1.42)
3/4
(19.05)
.824
(20.930)
360
(10.19)
247
(7.00)
199
(5.63)
170
(4.81)
151
(4.28)
137
(3.87)
126
(3.56)
117
(3.31)
110
(3.11)
104
(2.94)
1
(25.4)
1.049
(26.645)
678
(19.19)
466
(13.19)
374
(10.59)
320
(9.06)
284
(8.04)
257
(7.27)
237
(6.71)
220
(6.23)
207
(5.86)
195
(5.52)
1-1/4
(31.75)
1.380
(35.052)
1350
(38.22)
957
(27.09)
768
(22.25)
657
(18.60)
583
(16.50)
528
(14.95)
486
(13.76)
452
(12.79)
424
(12.00)
400
(11.33)
1-1/2
(38.1)
1.610
(40.894)
2090
(59.18)
1430
(40.49)
1150
(32.56)
985
(27.89)
873
(24.72)
791
(22.39)
728
(20.61)
677
(19.17)
635
(17.98)
600
(17.00)
2
(50.8)
2.067
(52.502)
4020
(113.83)
2760
(78.15)
2220
(62.86)
1900
(53.80)
1680
(47.57)
1520
(43.04)
1400
(39.64)
1300
(36.81)
1220
(34.55)
1160
(32.844)
2-1/2
(63.5)
2.469
(67.713)
6400
(181.22)
4400
(124.59)
3530
(99.95)
3020
(85.51)
2680
(75.88)
2480
(70.22)
2230
(63.14)
2080
(58.89)
1950
(55.22)
1840
(52.10)
3
(76.2)
3.068
(77.927)
11300
(319.98)
7780
(220.30)
6250
(176.98)
5350
(151.49)
4740
(134.22)
4290
(121.47)
3950
(111.85)
3670
(103.92)
3450
(97.69)
3260
(92.31)
Length of Pipe - feet (m)
Page 29
Electrical
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic compo­
nents. Take precautions during furnace installation
and service to protect the furnace's electronic con­
trols. Precautions will help to avoid control exposure
to electrostatic discharge by putting the furnace, the
control and the technician at the same electrostatic
potential. Neutralize electrostatic charge by touch­
ing hand and all tools on an unpainted unit surface,
such as the gas valve or blower deck, before per­
forming any service procedure.
WARNING
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 side, clip the wire ties
that bundle the wires together. The excess wire must be
pulled into the blower compartment. Secure the excess
wire to the existing harness to protect it from damage.
Refer to figure 46 for unit field wiring. See figures 44 and 45
for icomfort Wi-Fi® thermostat wiring in communicating ap­
plications. Table 12 shows DIP switch and on-board link
settings for non-communicating thermostat applications.
Typical wiring schematic is shown in figure 46.
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.
NOTE - Unit nameplate states maximum current draw. See
table for maximum over-current protection.
Electric Shock Hazard. Can cause
injury or death. Unit must be properly
grounded in accordance with national
and local codes.
WARNING
Fire Hazard. Use of aluminum wire with this product
may result in a fire, causing property damage, severe
injury or death. Use copper wire only with this
product.
CAUTION
Failure to use properly sized wiring and circuit
breaker may result in property damage. Size wiring
and circuit breaker(s) per Product Specifications
bulletin (EHB) and unit rating plate.
INTERIOR MAKE-UP BOX INSTALLATION
TABLE 9
SLP98UHV Model
Maximum Over-Current
Protection (Amps)
070-36B, 090-36C, 090-48C
15
090-60C, 110-60C, 135-60D
20
2 - Holes are on both sides of the furnace cabinet to facili­
tate wiring.
3 - Install a separate (properly sized) disconnect switch
near the furnace so that power can be turned off for
servicing.
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.
5 - Complete the wiring connections to the equipment.
Use the provided unit wiring and field wiring diagram
shown in figure 46 and table 12. Use 18-gauge wire or
larger that is suitable for Class II rating for thermostat
connections.
NOTE - Do NOT make a wire connection between
the room thermostat L terminal and the L terminal
of the SLP98UHV integrated control unless this is a
communicating thermostat installation with a noncommunicating outdoor unit.
MAKE-UP
BOX
Right Side
FIGURE 43
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) for the
USA and current Canadian Electric Code part 1 (CSA
standard C22.1) for Canada. A green ground wire is
provided in the field make-up box.
7 - One line voltage “EAC” 1/4” spade terminal is provided
on the furnace integrated control. Any electronic air
cleaner or other 120V accessory rated up to one amp
can be connected to this terminal with the neutral leg
Page 30
of the circuit being connected to one of the provided
neutral terminals. See figure 47 for location of terminal.
This terminal is energized when the indoor blower is
operating.
8 - One line voltage “HUM” 1/4” spade terminal is pro­
vided on the furnace integrated control. Any humidifier
or other 120V accessory rated up to one amp can be
connected to this terminal with the neutral leg of the cir­
cuit being connected to one of the provided neutral ter­
minals. See figure 47 for location of terminal. This ter­
minal is energized in the heating mode when the indoor
blower is operating.
9 - One 24V “H” terminal is provided on the furnace inte­
grated control terminal block. Any humidifier rated up
to 0.5 amp can be connected to this terminal with the
ground leg of the circuit being connected to either
ground or the “C” terminal. See figure 47 for location of
terminal.
10 -Install the room thermostat according to the instruc­
tions provided with the thermostat. See table 12 for
thermostat connections. If the furnace is being
matched with a heat pump, refer to the instruction
packaged with the dual fuel thermostat.
NOTE - The discharge air temperature sensor is intended
to be mounted downstream of the heat exchanger and air
conditioning coil. It must be placed in free airflow, where
other accessories (humidifiers, UV lights etc.) will not inter­
fere with its accuracy. Wiring distance between the furnace
and discharge air sensor should not exceed 10 ft. when
wired with 18-gauge thermostat wire.
The icomfort Wi-Fi® thermostat must be used in communi­
cating applications. Refer to the instructions provided with
the thermostat for installation, set-up and operation.
For optimal performance in non-communicating applica­
tions, Lennox recommends use of a ComfortSense® 7000
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
set-up for optimal variable rate capacity mode:
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).
Indoor Blower Speeds
NOTE - When the SLP98UHV is used with icomfort
Toucht thermostat, proper indoor blower speed
selections are made by the communicating thermo­
stat.
1 - When the thermostat is set to “FAN ON,” the indoor
blower will run continuously at a percentage of the sec­
ond-stage cooling speed when there is no cooling or
heating demand. The percentage is set using DIP
switches 6 and 7.
2 - When the SLP98UHV is running in the heating mode,
the integrated control will automatically adjust the
blower speed to match the furnace firing rate. This
speed can be adjusted up or down by 7.5% or 15% us­
ing DIP switches 14 through 16 for the low heat speed
and 17 through 19 for the high heat speed.
TABLE 10
Run Length — Non Communicating
Wire Run Length
AWG #
Insulation/Core Types
Less than 100' (30m)
18
More than 100' (30m)
16
Color-coded, temperature
rating 95ºF (35ºC) mini­
mum, solid core. (Class II
Rated Wiring)
3 - When there is a cooling demand, the indoor blower will
run on the cooling speed designated by the positions
of DIP switches 8 through 11.
Generator Use - Voltage Requirements
The following requirements must be kept in mind when
specifying a generator for use with this equipment:
TABLE 11
Run Length — Communicating
Wire Run Length
AWG #
Insulation/Core Types
Maximum length of wiring
for all connections on the
RSBus is limited to 1500
feet (457 meters).
18
Color-coded, temperature
rating 95ºF (35ºC) mini­
mum, solid core. (Class II
Rated Wiring)
S
S
S
Thermostat Selection
The SLP98UHV is designed to operate in a variable rate
capacity mode using a two-stage thermostat. The
SLP98UHV will automatically adjust firing rate based upon
thermostat cycle times.
Page 31
S
The furnace requires 120 volts + 10% (Range: 108
volts to 132 volts).
The furnace operates at 60 Hz + 5% (Range: 57 Hz to
63 Hz).
The furnace integrated control requires both polarity
and proper ground. Both polarity and proper grounding
should be checked before attempting to operate the
furnace on either permanent or temporary power.
Generator should have a wave form distortion of less
than 5% THD (total harmonic distortion).
icomfort Wi-Fi® Thermostat with SLP98UHV
and Non-Communicating Outdoor Unit
icomfort Wi-Fi® Thermostat
icomfort®-Enabled SLP98UHV Indoor Furnace
Non-Communicating Outdoor Air Conditioner
OPTIONAL
DISCHARGE
AIR SENSOR
icomfort Wi-Fi® Thermostat with SLP98UHV
and icomfort-ENABLED Outdoor Unit
icomfort Wi-Fi® Thermostat
icomfort®-Enabled SLP98UHV Indoor Furnace
icomfort®-Enabled Outdoor Air Conditioner or Heat Pump
icomfort®ENABLED
SLP98UHV
FURNACE
icomfort®ENABLED
SLP98UHV
FURNACE
OPTIONAL
DISCHARGE
AIR SENSOR
OPTIONAL
OUTDOOR
AIR SENSOR
icomfort Wi-Fi®
THERMOSTAT
OPTIONAL
OUTDOOR
AIR SENSOR
icomfort Wi-Fi®
THERMOSTAT
icomfort®- ENABLED
OUTDOOR AIR CONDITIONING
OR HEAT PUMP UNIT
NON-COMMUNICATING
OUTDOOR AIR
CONDITIONING UNIT 1 OR 2 STAGE
CLIP Y1 TO Y2 FOR
TWO-STAGE OPERA­
TION
Outdoor Unit
Indoor Unit
Controller
icomfort Wi-Fi®
thermostat
Single wire to
terminal C
Single wire to
terminal C
Unused wires
Unused wires
Communicating systems using the icomfort Wi-Fi® thermostat require four ther­
mostat wires between the thermostat and the furnace/air handler control and four
wires between the outdoor unit and the furnace/air handler control. When a ther­
mostat cable with more than four wires is used, the extra wires must be properly
connected to avoid electrical noise. The wires must not be left disconnected.
Use wire nuts to bundle the four unused wires at each end of the cable. A
single wire should then be connected to the indoor unit end of the wire bundle
and attached to the “C” terminals as shown in the diagram above.
FIGURE 44
Page 32
Optional Accessories for use with any icomfort Touch® System
icomfort®ENABLED
SLP98UHV
FURNACE
NOTE: icomfort WiFi® THERMOSTAT SENSES HUMIDITY & CONTROLS
24V “H” OUTPUT (& 120V “H” OUTPUT) TO CYCLE HUMIDIFIER BASED
ON DEMAND. NO OTHER CONTROL OR HUMIDISTAT REQUIRED.
OPTIONAL OUTDOOR AIR SENSOR FOR USE WITH HU­
MIDIFIER (IF NOT ALREADY IN THE SYSTEM FOR OTHER
FUNCTIONS. BUILT INTO ALL icomfort® OUTDOOR UNITS).
DISCHARGE AIR SENSOR
icomfort Wi-Fi®
THERMOSTAT
NOTE: 24V UV LIGHT
APPLICATIONS
Furnace transformer will not have ad­
equate va to power 24v UV light ap­
plications. An additional transformer
for UV light applications is required.
icomfort®ENABLED
SLP98UHV
FURNACE
icomfort®ENABLED
SLP98UHV
FURNACE
HEPA BYPASS FIL­
TER X2680 HEPA
INTERLOCK KIT
icomfort®- ENABLED
OUTDOOR AIR
CONDITIONING OR
HEAT PUMP UNIT
PASS INDOOR BLOWER
MOTOR COMMON WIRE
THROUGH CURRENT LOOP.
SEE HEPA INTERLOCK KIT
FOR INSTALLATION DE­
TAILS
icomfort®ENABLED
SLP98UHV
FURNACE
LVCS VENTILATION
CONTROL SYSTEM
SEE LVCS VENTILATION
INSTRUCTIONS FOR
DAMPER & SENSOR WIRING
icomfort®ENABLED
SLP98UHV
FURNACE
NON-COMMUNICATING
1 OR 2 STAGE AC OR HP UNIT
(C)
(C)
(disables out­
door unit only)
FIGURE 45
Page 33
TABLE 12
Field Wiring Connections for Non-Communicating Thermostat Applications
Thermostat
DIP Switch Settings and On-Board Links (figure 47)
W914
W915
(DS to R)
W951
Dehumidifi­
(Y1 to Y2)
DIP Switch 1
(O to R)
Two-Stage
cation or
Heat Pumps
Cooling
Harmony
III
1Heat / 1 Cool
NOTE - Use DIP
switch 3 to set
second-stage
heat ON delay.
OFF-7 minutes.
ON-12 minutes.
ON
1 Heat / 2 Cool
NOTE - Use DIP
switch 3 to set
second-stage
heat ON delay.
OFF-7 minutes.
ON-12 minutes.
ON
1 Heat / 2 Cool
with t'stat with
dehumidification
mode
NOTE - Use DIP
switch 3 to set
second-stage
heat ON delay.
OFF-7 minutes.
ON-12 minutes.
ON
Intact
Intact
Intact
Wiring Connections
S1
T'STAT
CONTROL
TERM. STRIP
OUTDOOR
UNIT
*
Cut
Intact
Intact
S1
T'STAT
CONTROL
TERM. STRIP
OUTDOOR
UNIT
*
Cut
Cut
Intact
S1
T'STAT
CONTROL
OUTDOOR
TERM. STRIP
UNIT
*
* “R” required on some units.
Page 34
TABLE 12
Field Wiring for Non-Communicating Applications (Continued)
Thermostat
2 Heat / 2 Cool
DIP Switch Settings and On-Board Links (figure 47)
W914
W915
(DS to R)
(Y1 to Y2)
W951
Dehumidifi­
Two-Stage
DIP Switch 1
(O to R)
cation or
Cooling
Heat Pumps
Harmony
III
OFF
Cut
Intact
Intact
Wiring Connections
S1
T'STAT
CONTROL
TERM. STRIP
OUTDOOR
UNIT
*
2 Heat / 2 Cool
with t'stat with
dehumidifica­
tion mode
OFF
Cut
Cut
Intact
S1
T'STAT
CONTROL OUTDOOR
TERM. STRIP
UNIT
*
2 Heat / 1 Cool
OFF
Intact
Intact
Intact
S1
T'STAT
CONTROL
TERM. STRIP
OUTDOOR
UNIT
*
* “R” required on some units.
Page 35
TABLE 12
Field Wiring for Non-Communicating Applications (Continued)
Thermostat
Dual Fuel
Single-Stage
Heat Pump
DIP Switch Settings and On-Board Links (figure 47)
W914
W915
(DS to R)
W951
Dehumidifi­
(Y1 to Y2)
DIP Switch
(O to R)
Two-Stage
cation or
Heat Pumps
Cooling
Harmony
III
DIP Switch 1
OFF
Intact
Intact
Cut
Wiring Connections
L7742U
T'STAT
CONTROL
TERM. STRIP
HEAT PUMP
H
ComfortSense®
7000 L7742U
thermostat w/
dual fuel capa­
bilities
Capable of
2-stage gas
heat control
67M41*
L
L
Y
Y2
D
B
Y2
T
outdoor
sensor
T
Dual Fuel
Two Stage
Heat Pump
DIP Switch 1
OFF
Cut
Intact
Cut
L7742U
T'STAT
CONTROL TERM.
STRIP
HEAT PUMP
H
ComfortSense®
67M41*
7000 L7742U
thermostat w/
dual fuel capa­
bilities
Capable of
2-stage gas
heat control
L
L
Y2
Y2
D
B
T
T
out blue
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 SLP98UHV
integrated control.
Page 36
TYPICAL SLP98UHV WIRING DIAGRAM
FIGURE 46
Page 37
Integrated Control
NEUTRAL
TERMINALS
COMBUSTION
AIR INDUCER
CONNECTOR
IGNITOR
CONNECTOR
FLAME
SENSE
DIAGNOSTIC
PUSH BUTTON
LINE VOLTAGE
TERMINALS
+
HUM
DIP SWITCHES
EAC
OUTDOOR AIR
SENSOR
TERMINALS
INDOOR
BLOWER
CONNECTOR
7-SEGMENT
DIAGNOSTIC LED
W915 Y1 TO Y2
W951 R TO O
DISCHARGE AIR
SENSOR
TERMINALS
FACTORY TEST
HEADER PINS.
FACTORY USE ONLY.
W914 R TO DS
W915
W951
W914
TB83 OUTDOOR
L - use only with
communicating T'stat and
non-communicating outdoor
unit.
TB84 INDOOR
RS-BUS LINK (TB82, future use)
I+ = DATA HIGH CONNECTION
I - = DATA LOW CONNECTION
THERMOSTAT CONNECTIONS (TB1)
DS = DEHUMIDIFICATION SIGNAL
W2 = HEAT DEMAND FROM 2ND STAGE T/STAT
RS-BUS OUTDOOR (TB83)
R = 24VAC
I + = DATA HIGH CONNECTION
I - = DATA LOW CONNECTION
C = 24VAXC COMMON
W1 = HEAT DEMAND FROM 1ST STAGE T/STAT
R = CLASS 2 VOLTAGE TO THERMOSTAT
G = MANUAL FAN FROM T'STAT
RS-BUS INDOOR (TB84)
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)
Y1 = THERMOSTAT 1ST STAGE COOL SIGNAL
Y2 = THERMOSTAT 2ND STAGE COOL SIGNAL
1/4” QUICK CONNECT TERMINALS
O = THERMOSTAT SIGNAL TO HEAT PUMP
REVERSING VALVE
HUM = 120 VAC OUTPUT TO HUMIDIFIER
XMFR = 120 VAC OUTPUT TO TRANSFORMER
H = 24V HUMIDIFIER OUTPUT. DO NOT CONNECT
TO COMFORTSENSE® THERMOSTAT
LI = 120 VAC INPUT TO CONTROL
CIRC = 120 VAC OUTPUT TO CIRCULATING BLOWER
L = USE ONLY WITH A COMMUNICATING
THERMOSTAT AND A NON-COMMUNICATING
OUTDOOR UNIT
EAC = 120 VAC OUTPUT TO ELECTRICAL AIR CLEANER
NEUTRALS = 120 VAC NEUTRAL
DH = DEHUMIDIFICATION OUTPUT
COMMUNICATING THERMOSTAT ONLY
FIGURE 47
.............
Page 38
TABLE 13
Thermostat Selection Switch Settings
Operation
Thermostat
Switch 1
Switch 2
Switch 3
Variable Capacity Heat
(35% to 100%)
Two-Stage
Off
On
Off
Three-Stage Heat
(35%, 70%, 100%)
Single-Stage
On
Off
2nd stage delay
OFF = 7 minutes
ON = 12 minutes
3rd stage delay
10 minutes fixed
Two-Stage Heat (W1 70%, W2 100%)
Two-Stage
Off
Off
Off
NOTE - When the SLP98UHV is used with an icomfort
Toucht communicating thermostat, all indoor blower
speed selections and DIP switch settings are made by the
communicating thermostat.
SLP98UHV units are equipped with an integrated control.
This control manages ignition timing, combustion air induc­
er speed, heating mode fan off delays and indoor blower
speeds based on selections made using the icomfort
Toucht thermostat or the control DIP switches and onboard links. The control includes an internal Watchguard
feature which automatically resets the ignition control
when it has been locked out.
NOTE - All DIP switches are factory shipped in the
“OFF” position.
Heating Operation DIP Switch Settings -- Figure 47
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 twostage thermostat. If a single-stage thermostat is to be used,
the DIP switch must be repositioned. See table 13.
Switch 2 -- Operating Mode with Two-Stage Thermo­
stat -- If a two-stage thermostat is used, the furnace can
operate in either variable-capacity or conventional twostage mode. When variable-capacity mode is selected, the
firing rate of the unit is varied to maximize comfort. Conven­
tional two-stage mode is the factory default setting. See
table 13.
and 5 on the integrated control. The unit is shipped from the
factory with a blower-off delay of 90 seconds. The bloweroff delay affects comfort and is adjustable to satisfy individ­
ual applications. Adjust the blower off delay to achieve a
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
tings provide higher supply air temperatures. Table 14 pro­
vides the blower-off timings that will result from different
switch settings.
TABLE 14
Blower-Off Delay Switch Settings
Blower-Off Delay
(Seconds)
60
90 (factory)
120
180
Switch 5
Off
Off
On
On
On
Off
Off
On
Indoor Blower Operation DIP Switch Settings
Switches 6 and 7 -- Continuous Indoor Fan Operation­
Blower Speed -- The unit is shipped from the factory with
the DIP switches positioned for medium low (2) speed dur­
ing continuous indoor blower operation. The table below
provides the continuous blower speeds that will result from
different switch settings. Refer to tables beginning on page
42 for corresponding cfm values.
TABLE 15
Continuous Indoor Blower Operation -- Blower Speeds
Switch 3 -- Second-Stage Heat On Delay -- If a singlestage thermostat is used, the integrated control can be
used to energize second-stage heat after either 7 minutes
or 12 minutes of first-stage heat operation. See table 13.
Switches 4 and 5 -- 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 4
Switch 4
Speed
1 - Low (28%)*
2 - Medium Low
(38%)* Factory
3 - Medium High
(70%)*
Switch 6
Off
Switch 7
On
Off
Off
On
Off
4 - High (100%)*
On
On
* Percentage of high speed cooling
Page 39
TABLE 18
Cooling Mode Blower Speed Ramping
Ramping Option
Switch 12
Switch 13
A (Factory)
Off
Off
B
On
Off
C
Off
On
D
On
On
Switches 8 and 9 -- 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
during the cooling mode. The table below provides the
cooling mode blower speeds that will result from different
switch settings. Refer to tables beginning on page 42 for
corresponding cfm values.
TABLE 16
Cooling Mode Blower Speeds
Speed
1 - Low
2 - Medium Low
3 - Medium High
4 - High (Factory)
Switch 8
On
Off
On
Off
D
D
Switch 9
On
On
Off
Off
D
D
Switches 10 and 11 -- Cooling Mode Blower Speed Ad­
justment -- 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 -10% to better suit the application. Table
17 provides blower speed adjustments that will result from
different switch settings. Refer to tables beginning on page
42 for corresponding cfm values.
With switches 10 and 11 set to ON, motor will bypass ramp­
ing profiles and all delays and will immediately run at se­
lected COOLING speed upon a call for cool. LED will con­
tinue to operate as normal. This mode is used to check
motor operation.
TABLE 17
Cooling Mode Blower Speed Adjustment
Adjustment
+10% (approx.)
DEFAULT COOL
CFM
Switch 10
On
Off
Off
-10% (approx.)
MOTOR TEST
Off
On
On
On
Ramping Option A (Factory Selection)
Motor runs at 50% for 30 seconds.
Motor then runs at 82% for approximately 7-1/2 minu­
tes.
If demand has not been satisfied after 7-1/2 minutes,
motor runs at 100% until demand is satisfied.
Once demand is met, motor runs at 50% for 30 sec­
onds then ramps down to stop.
7 1/2 MIN
82% CFM
OFF
1/2 MIN
50% CFM
OFF
1/2 MIN
50% CFM
COOLING DEMAND
Ramping Option B
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.
7 1/2 MIN
82%CFM
OFF
100% CFM
OFF
COOLING DEMAND
Switch 11
Off
Ramping Option C
Motor runs at 100% until demand is satisfied.
Once demand is met, motor runs at 100% for 45 sec­
onds then ramps down to stop.
100% CFM
OFF
Switches 12 and 13 -- 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
blower motor performance. Table 18 provides the cooling
mode blower speed ramping options that will result from
different switch settings. The cooling mode blower speed
ramping options are detailed below.
100%
CFM
COOLING DEMAND
100% CFM
45 SEC.
Ramping Option D
Motor runs at 100% until demand is satisfied.
NOTE - The off portion of the selected ramp profile only ap­
plies during heat pump operation in dual fuel applications.
Page 40
Once demand is met, motor ramps down to stop.
OFF
100% CFM
COOLING
DEMAND
OFF
OFF
Switches 14 through 19 -- Heating Mode Blower Speed
-- These switches are factory set at the OFF position which
provides 100 % of normal speed during HIGH HEAT de­
mand, 70% of normal speed during MID-RANGE HEAT
demand and 35% of normal speed during LOW HEAT de­
mand. Switches 14, 15 and 16 are used to adjust the LOW
HEAT blower motor speed. Switches 17, 18 and 19 are
used to adjust the HIGH HEAT blower motor speed. Table
19 provides the heating mode blower speeds that will result
from different switch settings. Refer to tables beginning on
page 42 for corresponding cfm values.
TABLE 19
Low Heat Blower Speeds
Blower
DIP SWITCH SETTINGS
Thermostat
Speed
Demand
Adjust­
14
15
16
ments
+15%
On
Off
On
+7.5%
On
Off
Off
Low Heat
Normal
Off
Off
Off
(R to W1)
-7.5%
On
On
Off
-15%
On
On
On
TABLE 20
High Heat Blower Speeds
Blower
DIP SWITCH SETTINGS
Thermostat
Speed
Demand
Adjust­
17
18
19
ments
+15%
On
Off
On
+7.5%
On
Off
Off
High Heat
(R to
Normal
Off
Off
Off
W1 & W2)
-7.5%
On
On
Off
-15%
On
On
On
On-Board Links
On-Board links must be clipped (when applicable) before
unit is placed into operation with a non-communicating
thermostat.
On-Board Link W914 DS to R (Figure 47)
On-board link W914, is a clippable connection between ter­
minals DS and R 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 21 for operation sequence in ap­
plications including SLP98UHV, a thermostat which fea­
tures humidity control and a single-speed outdoor unit.
Table 22 gives the operation sequence in applications with
a two-speed outdoor unit.
On-Board Link W951 R to O (Figure 47)
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.
On-Board Link W915 Y1 to Y2 (Figure 47)
On-board link W915 is a clippable connection between ter­
minals Y1 and Y2 on the integrated control. W915 must be
cut if two-stage cooling will be used. If the link is not cut the
outdoor unit will operate in second-stage cooling only.
Diagnostic LED (Figure 47)
The seven-segment diagnostic LED displays operating
status, target airflow, error codes and other information.
The table beginning on Page 56 lists diagnostic LED
codes.
Diagnostic Push Button (Figure 47)
The diagnostic push button is located adjacent to the
seven-segment diagnostic LED. This button is used to en­
able the Error Code Recall mode and the Field Test mode.
Press the button and hold it to cycle through a menu of op­
tions. Every five seconds a new menu item will be dis­
played. When the button is released, the displayed item will
be selected. Once all items in the menu have been dis­
played, the menu resumes from the beginning until the but­
ton is released.
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.
Field Test Mode
Use the diagnostic push button to scroll through the menu
as described above. Release the button when the LED
flashes “-” to select the Field Test mode.
While in the Field Test mode the technician can:
D Initiate furnace ignition and move to and hold low-fire
rate by applying a R to W1 jumper.
D Initiate furnace ignition sequence and move to and
hold high-fire rate by applying a jumper from R to W1
and W2.
D Initiate furnace ignition sequence and move to and
hold mid-fire rate by applying a jumper to R and W2.
D Apply then remove the jumper from R to W1 and W2 to
change the firing rate from low fire to mid fire and high
fire.
D A vent calibration sequence can be initiated even if a
thermostat signal is not present. Press and hold the
push button until a solid “C” is displayed. Release the
button and calibration will begin. The furnace will per­
form the high-fire and low-fire pressure switch calibra­
tions and display “CAL”. After calibration, the LED will
return to the flashing “-” display.
During Field Test mode operation, all safety switches are
still in the circuit (they are not by-passed) and indoor blower
performance and timings will match DIP switch selections.
Current furnace firing rate, indoor blower CFM and flame
signal will be displayed. To exit the Field Test mode, press
and hold the button. The menu will resume from the begin­
ning. Also, cycle the main power to exit the Field Test
mode. The integrated control will automatically exit the
Field Test mode after 45 minutes of operation.
Page 41
BLOWER DATA
SLP98UH070V36B BLOWER PERFORMANCE (less filter)
BOTTOM RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections
Heating Input Range and Blower Volume - CFM
35%
40%
50%
60%
70%
80%
90%
100%
Increase (+15%) Heat CFM
489
538
636
735
833
931
1030
1128
Increase (+7.5%) Heat CFM
450
496
588
680
772
864
956
1048
Default Heat CFM
410
453
539
624
710
796
881
967
Decrease (-7.5% ) Heat CFM
380
419
498
578
657
736
815
895
Decrease (-15% ) Heat CFM
349
385
458
531
604
676
749
822
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Increase (+10%) Cool CFM
Blower Speed Selections
First Stage Cool Speed - cfm
Second Stage Cool Speed - cfm
Low
MediumLow
Medium
High
High
(Default)
Low
MediumLow
Medium
High
High
(Default)
600
740
840
970
860
1060
1215
1365
Default Cool CFM
555
665
770
855
810
960
1130
1265
Decrease (-10%) Cool CFM
500
600
680
790
705
840
1005
1140
SLP98UH090V36C BLOWER PERFORMANCE (less filter)
BOTTOM RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections
Heating Input Range and Blower Volume - CFM
35%
40%
50%
60%
70%
80%
90%
100%
Increase (+15%) Heat CFM
687
734
827
921
1014
1108
1201
1295
Increase (+7.5%) Heat CFM
654
697
782
867
953
1038
1123
1209
Default Heat CFM
621
660
737
814
891
968
1045
1122
Decrease (-7.5% ) Heat CFM
581
616
687
757
828
899
970
1041
Decrease (-15% ) Heat CFM
540
572
637
701
766
830
895
959
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Blower Speed Selections
First Stage Cool Speed - cfm
Low
MediumLow
Medium
High
Second Stage Cool Speed - cfm
High
(Default)
Low
MediumLow
Medium
High
High
(Default)
Increase (+10%) Cool CFM
625
710
830
950
875
1040
1210
1360
Default Cool CFM
565
670
760
860
800
945
1100
1240
Decrease (-10%) Cool CFM
520
610
685
785
720
840
970
1115
The effect of static pressure is included in air volumes shown.
The following control configurations are available. See Installation Instructions for details and DIP switch settings.
Heat Modes Available (Heating Blower Performance Table):
Single stage thermostat:
- 35%, 70%, 100% input (three-stage) with time delays in-between
Two-stage thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts firing rate based on first- and second-stage cycle times
- W1 demand at 70% input, W2 demand at 100% input. No delay between stages
icomfort Touch™ Communicating Thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts firing rate based on first- and second-stage cycle times
- 35%, 60%, 80%, 100% (four-stage) with time delays in-between
Cool Mode Available (Cooling Blower Performance table):
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan speeds are approximately 28%, 38%, 70% and 100% (DIP switch selectable) of the same second-stage COOL speed position
minimum 250 cfm.
Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 250 cfm.
Page 42
BLOWER DATA
SLP98UH090V48C BLOWER PERFORMANCE (less filter)
BOTTOM RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections
Heating Input Range and Blower Volume - CFM
35%
40%
50%
60%
70%
80%
90%
100%
Increase (+15%) Heat CFM
769
835
Increase (+7.5%) Heat CFM
713
776
968
1101
1234
1367
1500
1633
902
1028
1155
1281
1407
1534
Default Heat CFM
656
Decrease (-7.5% ) Heat CFM
595
716
836
955
1075
1195
1314
1434
652
767
882
997
1112
1227
1342
Decrease (-15% ) Heat CFM
534
589
699
809
919
1029
1139
1249
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Increase (+10%) Cool CFM
Blower Speed Selections
First Stage Cool Speed - cfm
Second Stage Cool Speed - cfm
Low
MediumLow
Medium
High
High
(Default)
Low
MediumLow
Medium
High
High
(Default)
840
1005
1155
1315
1165
1375
1580
1770
Default Cool CFM
780
915
1045
1190
1075
1265
1440
1645
Decrease (-10%) Cool CFM
690
835
955
1070
935
1145
1320
1465
SLP98UH090V60C BLOWER PERFORMANCE (less filter)
BOTTOM RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections
Heating Input Range and Blower Volume - CFM
35%
40%
50%
60%
70%
80%
90%
100%
Increase (+15%) Heat CFM
583
665
830
995
1159
1324
1488
1653
Increase (+7.5%) Heat CFM
540
618
774
930
1085
1241
1397
1553
Default Heat CFM
497
571
718
865
1012
1159
1306
1453
Decrease (-7.5% ) Heat CFM
439
507
644
781
917
1054
1191
1328
Decrease (-15% ) Heat CFM
380
443
570
697
823
950
1076
1203
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Increase (+10%) Cool CFM
Blower Speed Selections
First Stage Cool Speed - cfm
Second Stage Cool Speed - cfm
Low
MediumLow
Medium
High
High
(Default)
Low
MediumLow
Medium
High
High
(Default)
1050
1270
1445
1620
1590
1815
2010
2195
Default Cool CFM
975
1120
1295
1460
1460
1645
1845
2010
Decrease (-10%) Cool CFM
865
1010
1120
1290
1320
1500
1645
1860
The effect of static pressure is included in air volumes shown.
The following control configurations are available. See Installation Instructions for details and DIP switch settings.
Heat Modes Available (Heating Blower Performance Table):
Single stage thermostat:
- 35%, 70%, 100% input (three-stage) with time delays in-between
Two-stage thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts firing rate based on first- and second-stage cycle times
- W1 demand at 70% input, W2 demand at 100% input. No delay between stages
icomfort Touch™ Communicating Thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts firing rate based on first- and second-stage cycle times
- 35%, 60%, 80%, 100% (four-stage) with time delays in-between
Cool Mode Available (Cooling Blower Performance table):
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan speeds are approximately 28%, 38%, 70% and 100% (DIP switch selectable) of the same second-stage COOL speed position
minimum 380 cfm.
Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 380 cfm.
Page 43
BLOWER DATA
SLP98UH110V60C BLOWER PERFORMANCE (less filter)
BOTTOM RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections
Heating Input Range and Blower Volume - CFM
35%
40%
50%
60%
70%
80%
90%
100%
Increase (+15%) Heat CFM
767
861
1049
1237
1424
1612
1800
1988
Increase (+7.5%) Heat CFM
738
825
1000
1174
1349
1524
1699
1874
Default Heat CFM
708
789
951
1112
1274
1436
1597
1759
Decrease (-7.5% ) Heat CFM
655
731
883
1035
1187
1339
1491
1644
Decrease (-15% ) Heat CFM
602
673
816
958
1101
1243
1386
1528
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Increase (+10%) Cool CFM
Blower Speed Selections
First Stage Cool Speed - cfm
Second Stage Cool Speed - cfm
Low
MediumLow
Medium
High
High
(Default)
Low
MediumLow
Medium
High
High
(Default)
1060
1245
1345
1545
1560
1740
1930
2125
Default Cool CFM
970
1145
1265
1395
1405
1565
1775
1945
Decrease (-10%) Cool CFM
885
1025
1110
1250
1270
1425
1610
1770
SLP98UH135V60D BLOWER PERFORMANCE (less filter)
BOTTOM RETURN AIR
HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range
Heating Adjust CFM Selections
Heating Input Range and Blower Volume - CFM
35%
40%
50%
60%
70%
80%
90%
100%
Increase (+15%) Heat CFM
949
1033
1200
1367
1534
1701
1868
2035
Increase (+7.5%) Heat CFM
879
957
1113
1269
1426
1582
1738
1895
Default Heat CFM
808
881
1026
1172
1317
1463
1608
1754
Decrease (-7.5% ) Heat CFM
748
817
956
1095
1235
1374
1513
1652
Decrease (-15% ) Heat CFM
687
753
886
1019
1152
1284
1417
1550
COOLING BLOWER PERFORMANCE - 0 through 1.0 in. w.g. External Static Pressure Range
Cooling Adjust CFM
Selections
Blower Speed Selections
First Stage Cool Speed - cfm
Second Stage Cool Speed - cfm
Low
MediumLow
Medium
High
High
(Default)
Low
MediumLow
Medium
High
High
(Default)
Increase (+10%) Cool CFM
1070
1260
1410
1555
1565
1750
1970
2190
Default Cool CFM
980
1115
1255
1430
1445
1615
1805
1985
Decrease (-10%) Cool CFM
865
1020
1115
1280
1290
1470
1650
1805
The effect of static pressure is included in air volumes shown.
The following control configurations are available. See Installation Instructions for details and DIP switch settings.
Heat Modes Available (Heating Blower Performance Table):
Single stage thermostat:
- 35%, 70%, 100% input (three-stage) with time delays in-between
Two-stage thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts firing rate based on first- and second-stage cycle times
- W1 demand at 70% input, W2 demand at 100% input. No delay between stages
icomfort Touch™ Communicating Thermostat:
- Variable Rate Capacity Mode - furnace automatically adjusts firing rate based on first- and second-stage cycle times
- 35%, 60%, 80%, 100% (four-stage) with time delays in-between
Cool Mode Available (Cooling Blower Performance table):
First stage COOL (two-stage air conditioning units only) is approximately 70% of the same second stage COOL speed position.
Continuous Fan speeds are approximately 28%, 38%, 70% and 100% (DIP switch selectable) of the same second-stage COOL speed position
minimum 450 cfm.
Lennox Harmony III™ Zoning System Applications - Minimum blower speed is 450 cfm.
Page 44
TABLE 21
COOLING OPERATING SEQUENCE
SLP98UHV and Single-Stage Outdoor Unit
OPERATING
SEQUENCE
SYSTEM DEMAND
Demand
System
Condition
Step
1st
stage
SYSTEM RESPONSE
Relative Humidity
Compressor
Blower
CFM
(COOL)
O
G
Status
D*
On
On
Acceptable
24
VAC
High
100%
Comments
NO CALL FOR DEHUMIDIFICATION
Normal Operation
1
On
Compressor and indoor
blower follow thermostat
demand
BASIC MODE (only active on a Y1 thermostat demand)
Normal Operation
1
On
On
On
Acceptable
24
VAC
High
100%
Dehumidification
Call
2
On
On
On
Demand
0
VAC
High
70%
Thermostat energizes Y1
and de-energizes D on a
call for de-humidification
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Operation
1
On
On
On
Acceptable
24
VAC
High
100%
Dehumidification
call
2
On
On
On
Demand
0
VAC
High
70%
Dehumidification
call ONLY
1
On
On
On
Demand
0
VAC
High
70%
On-board links at indoor unit with a single-stage outdoor unit:
With Condensing unit - Cut W914 (R to DS) on SureLight® control;
With Heat Pump - Cut W914 (R to DS) & W951 (R to O)on SureLight®
control.
*ComfortSense® 7000 thermostat only
Page 45
Dehumidification mode
begins when humidity is
greater than set point
Thermostat will keep out­
door unit energized after
cooling temperature set­
point has been reached in
order to maintain room
humidity setpoint.
TABLE 22
COOLING OPERATING SEQUENCE
SLP98UHV and Two-Stage Outdoor Unit
OPERATING
SEQUENCE
SYSTEM DEMAND
Demand
System
Condition
Step
1st
stage
2nd
stage
SYSTEM RESPONSE
Relative Humidity
Compressor
Blower
CFM
(COOL)
O
G
Status
D*
On
On
Acceptable
24
VAC
Low
70%
On
On
Acceptable
24
VAC
High
100%
Comments
NO CALL FOR DEHUMIDIFICATION
Normal Operation Y1
1
On
Normal Operation Y2
2
On
On
Compressor and indoor
blower follow thermostat
demand
ROOM THERMOSTAT CALLS FOR FIRST STAGE COOLING
BASIC MODE (only active on a Y1 thermostat demand)
Normal Operation
1
On
Dehumidification
Call
2
On
On
On
On
Acceptable
24
VAC
Low
70%
On
On
Demand
0
VAC
High
70%
Thermostat energizes
2nd stage and de-ener­
gizes D on a call for dehumidification
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Operation
1
On
Dehumidification
call
2
On
Dehumidification
call ONLY
1
On
On
On
On
On
Acceptable
24
VAC
Low
70%
On
On
Demand
0
VAC
High
70%
On
On
Demand
0
VAC
High
70%
Dehumidification mode
begins when humidity is
greater than set point
Thermostat will keep out­
door unit energized after
cooling temperature set­
point has been reached
in order to maintain room
humidity setpoint.*
ROOM THERMOSTAT CALLS FOR FIRST AND SECOND STAGE COOLING
BASIC MODE (only active on a Y1 thermostat demand)
Normal Operation
1
On
On
On
On
Acceptable
24
VAC
High
100%
Dehumidification
Call
2
On
On
On
On
Demand
0
VAC
High
70%
Thermostat energizes
2nd stage and de-ener­
gizes D on a call for dehumidification
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Operation
1
On
Dehumidification
call
2
On
Dehumidification
call ONLY
1
On
On
On
Acceptable
24
VAC
Low
70%
On
On
On
Demand
0
VAC
High
70%
On
On
On
Demand
0
VAC
High
70%
On-board links at indoor unit with a two-stage outdoor unit:
Cut factory link from Y1 to Y2 or cut W915 (Y1 to Y2) on SureLight® inte­
grated control.
With Condensing unit - Cut W914 (R to DS) on SureLight® integrated control;
With Heat Pump - Cut W914 (R to DS) & W951 (R to O) on SureLight®
integrated control.
*ComfortSense® 7000 thermostat only
Page 46
Dehumidification mode
begins when humidity is
greater than set point
Thermostat will keep out­
door unit energized after
cooling temperature set­
point has been reached
in order to maintain room
humidity setpoint.
Unit Start-Up
FOR YOUR SAFETY READ BEFORE OPERATING
WARNING
Do not use this furnace if any part has been underwa­
ter. A flood-damaged furnace is extremely danger­
ous. Attempts to use the furnace can result in fire or
explosion. Immediately call a qualified service tech­
nician to inspect the furnace and to replace all gas
controls, control system parts, and electrical parts
that have been wet or to replace the furnace, if
deemed necessary.
WARNING
BEFORE PLACING THE UNIT INTO OPERATION, smell
all around the furnace area for gas. Be sure to smell next to
the floor because some gas is heavier than air and will
settle on the floor.
The gas valve on the SLP98UHV is equipped with a gas
control switch. Use only your hand to move the control
switch. Never use tools. 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:
SLP98UHV units are equipped with an automatic ignition
system. Do not attempt to manually light burners on this
furnace. Each time the thermostat calls for heat, the burn­
ers will automatically light. The ignitor does not get hot
when there is no call for heat on units with this ignition sys­
tem.
Danger of explosion. Can cause injury
or product or property damage. Should
the gas supply fail to shut off or if
overheating occurs, shut off the gas
valve to the furnace before shutting off
the electrical supply.
WARNING
If you do not follow these instructions exactly, a fire
or explosion may result causing property damage,
personal injury or death.
Gas Valve Operation (Figure 48)
1 - STOP! Read the safety information at the beginning of
this section.
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.
Priming Condensate Trap
The condensate trap should be primed with water prior to
start-up to ensure proper condensate drainage. Either pour
10 fl. oz. (300 ml) of water into the trap, or follow these steps
to prime the trap:
1 - Follow the lighting instructions to place the unit into op­
eration.
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.
5 - Remove the access panel.
6 - Move the gas valve switch to the OFF position. See fig­
ure 48.
7 - Wait five minutes to clear out any gas. If you then smell
gas, STOP! Immediately call the gas supplier from a
neighbor's phone. Follow the gas supplier's instruc­
tions. If you do not smell gas go to next step.
8 - Move gas valve switch to the ON position. See figure
48. Do not force.
NEGATIVE AIR
PRESSURE PORT
GAS VALVE
POSITIVE AIR
PRESSURE PORT
2 - Set the thermostat to initiate a heating demand.
3 - Allow the burners to fire for approximately 3 minutes.
4 - Adjust the thermostat to deactivate the heating de­
mand.
5 - Wait for the combustion air inducer to stop. Set the
thermostat to initiate a heating demand and again al­
low the burners to fire for approximately 3 minutes.
6 - Adjust the thermostat to deactivate the heating de­
mand and again wait for the combustion air inducer to
stop. At this point, the trap should be primed with suffi­
cient water to ensure proper condensate drain opera­
tion.
Page 47
OUTLET
INLET
SUPPLY
MANIFOLD
PRESSURE
PRESSURE TAP
TAP
GAS VALVE SHOWN IN THE ON POSITION
FIGURE 48
9 - Replace the access panel.
10- Turn on all electrical power to to the unit.
11- Set the thermostat to desired setting.
NOTE - When unit is initially started, steps 1 through 11
may need to be repeated to purge air from gas line.
12- If the appliance will not operate, follow the instructions
“Turning Off Gas to Unit” and call the gas supplier.
Turning Off Gas to Unit
1 - Set the thermostat to the lowest setting.
2 - Turn off all electrical power to the unit if service is to be
performed.
3 - Remove the access panel.
4 - Move the gas valve switch to the OFF position.
5 - Replace the access panel.
Failure To Operate
If the unit fails to operate, check the following:
1 - Is the thermostat calling for heat?
2 - Are access panels securely in place?
3 - Is the main disconnect switch closed?
4 - Is there a blown fuse?
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?
7 - Is the manual main shut‐off valve open?
8 - Is the gas valve turned on?
9 - Is the unit ignition system in lock out? If the unit locks
out again, inspect the unit for blockages.
10 - Is blower harness connected to ignition control? Fur­
nace will not operate unless harness is connected.
NOTE - To obtain accurate reading, shut off all other gas
appliances connected to meter.
Supply Pressure Measurement
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. Replace the
threaded plug after measurements have been taken.
Manifold Pressure Measurement (Figure 49)
To correctly measure manifold pressure, the differential
pressure between the positive gas manifold and the nega­
tive burner box must be considered. Use pressure test
adapter kit (available as Lennox part 10L34) to assist in
measurement.
1 - Remove the threaded plug from the outlet side of the
gas valve and install a field-provided barbed fitting.
Connect measuring device “+” connection to barbed
fitting to measure manifold pressure.
2 - Tee into the gas valve regulator vent hose and con­
nect measuring device “-” connection.
3 - Start unit on low heat (35% rate) and allow 5 minutes
for unit to reach steady state.
4 - While waiting for the unit to stabilize, notice the flame.
Flame should be stable and should not lift from burner.
Natural gas should burn blue.
5 - After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in table
24.
6 - Repeat steps 3, 4 and 5 on high heat.
NOTE - Shut unit off and remove manometer as soon as an
accurate reading has been obtained. Take care to remove
barbed fitting and replace threaded plug.
Gas Pressure Measurement
CAUTION
Gas Flow (Approximate)
Do not attempt to make adjustments to the gas valve.
TABLE 23
GAS METER CLOCKING CHART
Seconds for One Revolution
Natural
LP
SLP98
Unit
1 cu ft
2 cu ft
1 cu ft
2 cu ft
Dial
Dial
Dial
DIAL
-70
55
110
136
272
-90
41
82
102
204
-110
33
66
82
164
-135
27
54
68
136
Natural-1000 btu/cu ft
LP-2500 btu/cu ft
Furnace should operate at least 5 minutes before checking
gas flow. Determine time in seconds for two revolutions of
gas through the meter. (Two revolutions assures a more
accurate time.) Divide by two and compare to time in table
23 below. If manifold pressure matches table 27 and rate is
incorrect, check gas orifices for proper size and restriction.
Remove temporary gas meter if installed.
Operating Pressure Signal (Delta P) Measurement
(Figure 50)
Operating pressure signal can be taken while the manifold
pressure pressure check is taken (using two measuring de­
vices). Or, taken after the manifold pressure measurement
is complete.
1 - Tee into the negative line between the gas valve and
pressure switch and connect to measuring device
negative “-”.
2 - Tee into the positive line between the gas valve and
pressure switch and connect to measuring device
positive “+”.
3 - Start unit on low heat (35% rate) and allow 5 minutes
for unit to reach steady state.
4 - After allowing unit to stabilize for 5 minutes, record op­
erating pressure signal and compare to value given in
table 24.
5 - Repeat steps 3 on 4 high heat.
Page 48
MANIFOLD PRESSURE MEASUREMENT
Gas Valve
Field Installed
FIGURE 49
Operating Signal (Delta P) Measurement
Negative Port
Positive Port
Red and Black Tubing -
Black Tubing +
Gas Valve
Field Installed
Measuring Device
FIGURE 50
Page 49
TABLE 24
Manifold and Operating Signal Pressures in inches 0 - 7500 ft (0 - 2286 m)
SLP98
Firing
Rate
Manifold Pressure Nat Gas
Manifold Pressure LP/Propane
Operating Pressure Signal
(Delta P)
Min
Normal
Max
Min
Normal
Max
Min
Normal
Max
35%
0.4
0.5
0.6
1.2
1.5
1.8
0.25
0.30
0.35
70%
1.7
1.9
2.1
5.1
5.5
5.9
0.60
0.65
0.70
100%
3.2
3.5
3.8
9.5
10.0
10.5
1.10
1.15
1.20
NOTE - A natural to LP/propane gas changeover kit (table 27) is necessary to convert this unit. Refer to the changeover kit
installation instruction for the conversion procedure.
SLP98UHV units require no manifold pressure adjust­
Proper Combustion
ments for operation at altitudes up to 10,000 feet (3048 m)
Furnace should operate a minimum of 15 minutes with cor­
above sea level. Units installed at altitude of 7,501 to
rect manifold pressure and gas flow rate before checking
10,000 feet (2287 to 3048m) require a pressure switch
combustion. Take combustion sample beyond the flue out­
change per table 27. Table 27 also lists conversion kit re­
let and compare to the tables below. The maximum carbon
quirements.
monoxide reading should not exceed 50 ppm.
The® combustion air pressure switch is factory-set and re­
TABLE 25
quires no adjustment.
High Fire
TABLE 27
Model Input Size
CO2% For Nat CO2% For L.P.
Conversion Kit Requirements
070
090
110
7.6 - 8.6
Model
Input
Size
9.1 - 10.1
135
LP/Propane
Kit
High Altitude Pressure Switch Kit
0 - 10,000
(0 - 3048 m)
0 - 7,500
(0 - 2286 m)
7,501 - 10,000
(2287 - 3048m)
65W77
Not required
93W75
070
090
TABLE 26
Low Fire
CO2% For Nat
Model Input Size
070
110
135
CO2% For L.P.
5.7
7.2 - 8.2
5.3 - 6.3
6.8 - 7.8
Other Unit Adjustments
090
110
135
High Altitude Information
NOTE - In Canada, certification for installations at eleva­
tions over 4500 feet (1372 m) is the jurisdiction of local au­
thorities.
Primary Limit
The primary limit is located on the heating compartment
vestibule panel. This limit is factory set and require no ad­
justment.
Flame Rollout Switches (Two)
These manually reset switches are located on the inside of
the burner box. If tripped, check for adequate combustion
air before resetting.
Page 50
Pressure Switches (Two)
The pressure switches are located on the cold end header
box. These switches check for proper combustion air in­
ducer operation before allowing ignition trial. The switches
are factory-set and require no adjustment. Pressure switch
tubing installation is critical for safe operation. See figure
51.
PRESSURE SWITCH TUBING INSTALLATION
(shown in upflow position)
Electronic Ignition
The integrated control has an added feature of an internal
Watchguard control. The feature serves as an automatic
reset device 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.
Exhaust and Air Intake Pipe
1 - Check exhaust and air intake connections for tightness
and to make sure there is no blockage.
2 - Are pressure switches closed? Obstructed exhaust
pipe will cause unit to shut off at pressure switches.
Check termination for blockages.
3 - Reset manual flame rollout switches on burner box
cover.
Heating Sequence of Operation
Gas Valve
Cold End Header Box
2
3
1
4
High-Fire
Pressure Switch
Low-Fire
Pressure Switch
1 - Black tubing from front port on low-fire pressure switch to
positive port on the gas valve.
2 - Red and black tubing from rear port on low-fire pressure
switch to the negative port on the gas valve.
3 - Red and black tubing from front port on high-fire pressure
switch to negative port on cold end header box.
4 - Black tubing from rear port on high-fire pressure switch to
positive port on cold end header box.
FIGURE 51
Temperature Rise
After the furnace has been started and supply and return
air temperatures have been allowed to stabilize, check the
temperature rise with the unit operating at 100 percent fir­
ing rate. If necessary, adjust the blower speed to maintain
the temperature rise within the range shown on the unit
nameplate. Increase the blower speed to decrease the
temperature. Decrease the blower speed to increase the
temperature rise. Failure to adjust the temperature rise
may cause erratic limit operation.
The integrated control initiates a pressure switch calibra­
tion at the initial unit start-up on a call for heat. The ignition
control will also initiate a calibration any time main power is
turned off and back on and a heating demand is present .
Additional calibrations may be initiated by the service tech­
nician during field test sequence. The following heating se­
quence of operation assumes completion of a successful
calibration.
NOTE - In icomfort Toucht communicating applications,
the sequence of operation is the same but all DIP switch
settings are overidden by the thermostat.
NOTE - The thermostat selection DIP switch on the inte­
grated control is factory-set in the “TWO-STAGE” position.
Applications Using a Two-Stage Thermostat
A - Heating Sequence -- Control Thermostat Selection
DIP switch in “Two-Stage” Position (Factory Setting)
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 ignition speed, which is approximately the
same as the inducer speed at 70 percent firing rate.
2 - Once the control receives a signal that the low-fire
pressure switch has closed, the combustion air induc­
er begins a 15-second pre-purge in the ignition speed.
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 the ignition speed.
4 - After the 20-second warm-up period has ended, the
gas valve is energized and ignition occurs. At the
same time, the control module sends a signal to begin
an indoor blower 30-second ON-delay. When the
delay ends, the indoor blower motor is energized at a
speed that matches the firing rate. After the 10-second
Page 51
ignition stabilization delay expires, the inducer speed
is adjusted to the appropriate target rate. The inducer
will remain at the 70 percent speed as long as the ther­
mostat has a first-stage heating demand.
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 and on all subse­
quent calls for heat in the same heating cycle, the inte­
grated control energizes the combustion air inducer at
high speed. The control also checks the high-fire pres­
sure switch to make sure it is closed. As the inducer
speed is increased to high, the indoor blower motor is
adjusted to a speed which is appropriate for the target
rate.
7 - When the demand for high-fire (second stage) heat is
satisfied, the gas valve is de-energized and the fieldselected indoor blower off delay begins. The combus­
tion air inducer begins a 20-second post-purge period.
8 - When the combustion air post-purge period is com­
plete, the inducer is de-energized. The indoor blower
is de-energized at the end of the off delay.
Applications Using a Two-Stage Thermostat
B - Heating Sequence -- Control Thermostat Selection
DIP switch in “Variable Capacity” Position
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 ignition speed, which is approximately the
same as the inducer speed at 70 percent firing rate.
2 - Once the control receives a signal that the low-fire
pressure switch has closed, the combustion air induc­
er begins a 15-second pre-purge in low speed.
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 the ignition speed.
4 - After the 20-second warm-up period has ended, the
gas valve is energized and ignition occurs. At the
same time, the control module begins an indoor blow­
er 30-second ON-delay. When the delay ends, the in­
door blower motor is energized at a speed that
matches the firing rate. After the 10-second ignition
stabilization delay expires, the inducer speed is ad­
justed to the appropriate target rate. If the furnace is
operating in the initial heating cycle after power-up,
the initial firing rate will be approximately 35 percent.
The firing rate on subsequent cycles will be automati­
cally adjusted by the integrated control based on ther­
mostat cycles. The firing rate will vary and will range
from 35 percent to 90 percent. The furnace will contin­
ue this operation as long as the thermostat has a firststage heating demand.
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 either in­
creases the firing rate to 70 percent (if the current rate
is at or below 60 percent) or increases the firing rate
by 10 percent (if the current rate is above 60 percent).
If the call for heat continues 5 minutes beyond this ini­
tial upstage, the rate will be increased by 10 percent
every 5 minutes until the call for heat is satisfied or the
furnace reaches 100 percent rate. As the firing rate in­
creases, the indoor blower motor is adjusted to a
speed which is appropriate for the target rate.
6 - If second-stage heat demand is satisfied, but first
stage is still present, the furnace will continue to oper­
ate at the present firing rate until the heat cycle ends.
7 - When the demand for first- and second-stage heat is
satisfied, the gas valve is de-energized and the fieldselected indoor blower off delay begins. The combus­
tion air inducer begins a 20-second post-purge period.
8 - When the combustion air post-purge period is com­
plete, the inducer is de-energized. The indoor blower
is de-energized at the end of the off delay.
Applications Using A Single-Stage Thermostat
C - Heating Sequence -- Control Thermostat Selection
DIP switch in “Single-Stage” Position
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 the ignition speed, which is approximately the
same as the inducer speed at 70 percent firing rate.
2 - Once the control receives a signal that the low-fire
pressure switch has closed, the combustion air induc­
er begins a 15-second pre-purge at the ignition speed.
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 the ignition speed.
4 - After the 20-second warm-up period has ended, the
gas valve is energized and ignition occurs, which initi­
ates a 10-second ignition stabilization delay. At the
same time, the control module sends a signal to begin
an indoor blower 30-second ON-delay. When the
delay ends, the indoor blower motor is energized at a
speed which is appropriate for the firing rate. After the
10-second ignition stabilization delay expires, the in­
ducer speed is adjusted to 35 percent speed. The inte­
grated control also initiates a second-stage on delay
(factory-set at 7 minutes; adjustable to 12 minutes).
5 - If the heating demand continues beyond the secondstage on delay, the integrated control energizes the
combustion air inducer at 70 percent speed. The in­
door blower motor is adjusted to a speed which
matches the target rate. A fixed, 10-minute third-stage
on delay is initiated.
Page 52
6 - If the heating demand continues beyond the thirdstage on delay, the integrated control energizes the in­
ducer at high speed. The indoor blower motor is ad­
justed to a speed which is appropriate for the target
rate.
7 -When the thermostat heating demand is satisfied, the
gas valve is de-energized and the combustion air in­
ducer begins a 20-second post-purge. The field-se­
lected indoor blower off delay begins.
8 - When the combustion air post-purge period is com­
plete, the inducer is de-energized. The indoor blower
is de-energized at the end of the off delay.
Service
6 Check the cleanliness of blower assembly and clean
the housing, blower wheel and blower motor if neces­
sary.
7- Inspect the condensate drain and trap for leaks and
cracks. The drain and trap must also be cleaned and the
trap must be primed with water. Inspect the rubber
hoses connected to the pressure switches for cracks or
loose connections, replace as necessary. Remove the
rubber hoses from the cold end header box and inspect
for any blockage, clean as needed. If strainers are in­
stalled in the hoses remember to remove and clean be­
fore re­installing the hoses.
8- Evaluate the heat exchanger integrity by inspecting the
heat exchanger per the AHRI heat exchanger inspec­
tion procedure. This procedure can be viewed at
www.ahrinet.org
WARNING
ELECTRICAL SHOCK, FIRE,
OR EXPLOSION HAZARD.
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.
When servicing controls, label all wires prior to dis­
connecting. Take care to reconnect wires correctly.
Verify proper operation after servicing.
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.
Annual Furnace Maintenance
At the beginning of each heating season, and to comply
with the Lennox Limited Warranty, your system should
be checked as follows:
1- Check wiring for loose connections, voltage at indoor
unit and amperage of indoor motor.
9- Ensure sufficient combustion air is available to the fur­
nace. Fresh air grilles and louvers (on the unit and in the
room where the furnace is installed) must be properly
sized, open and unobstructed to provide combustion
air.
10 On condensing furnaces, inspect the furnace intake
and exhaust pipes to make sure they are in place, struc­
turally sound, without holes, blockage or leakage and
the exhaust pipe is sloped toward the furnace. Inspect
terminations to ensure they are free of obstructions and
are structurally sound. Inspect the furnace return air
duct connection to ensure the duct is sealed to the fur­
nace. Check for air leaks on supply and return ducts and
seal where necessary.
11 Inspect the furnace return air duct connection to ensure
the duct is sealed to the furnace. Check for air leaks on
supply and return ducts and seal where necessary.
12 Check the condition of the furnace cabinet insulation
and repair if necessary.
13 Perform a complete combustion analysis during the fur­
nace inspection to ensure proper combustion and oper­
ation. Consult Service Literature for proper combustion
values.
2- Check the condition of the belt and shaft bearings if ap­
plicable.
14 Verify operation of CO detectors and replace batteries
as required.
3- Inspect all gas pipe and connections for leaks.
Perform a general system test. Turn on the furnace to
check operating functions such as the start-up and shut-off
operation.
1 - Check the operation of the ignition system, inspect
and clean flame sensor. Check microamps before and
after. Check controls and safety devices (gas valve,
flame sensor, temperature limits). Consult Service
4- Check the cleanliness of filters and change if necessary
(monthly).
5 Check the condition and cleanliness of burners and
heat exchanger and clean if necessary.
Page 53
Manual for proper operating range. Thermal Limits
should be checked by restricting airflow and not dis­
connecting the indoor blower. For additional details,
please see Service and Application Note H­04­9.
2 - Verify that system total static pressure and airflow set­
tings are within specific operating parameters.
3 - Clock gas meter to ensure that the unit is operating at
the specified firing rate for each stage of operation.
Check supply, manifold and signal pressures at 35, 70
and 100% capacity as outlined in the unit Service Lit­
erature. If manifold pressure adjustment is necessary,
consult the Service Literature for unit specific informa­
tion on adjusting gas pressure. Not all gas valves are
adjustable. Verify correct temperature rise.
NOTE - After any heavy snow, ice or frozen fog event the
furnace vent pipes may become restricted. Always check
the vent system and remove any snow or ice that may be
obstructing the plastic intake or exhaust pipes.
Winterizing and Condensate Trap Care
1 - Turn off power to the unit.
2 - Have a shallow pan ready to empty condensate water.
3 - Remove the drain plug from the condensate trap and
empty water. Inspect the trap then reinstall the drain
plug and refill trap with water.
Cleaning the Burner Assembly
1 - Turn off electrical and gas power supplies to furnace.
Remove upper and lower furnace access panels.
2 - Disconnect the 2-pin plug from the gas valve.
3 - Remove the burner box cover.
4 - Disconnect the gas supply line from the gas valve. Re­
move gas valve/manifold assembly.
5 - Mark and disconnect sensor wire from the sensor. Dis­
connect wires from flame rollout switches.
6 - Remove four screws which secure burner box assem­
bly to vest panel. Remove burner box from the unit.
7 - Use the soft brush attachment on a vacuum cleaner to
gently clean the face of the burners. Visually inspect
the inside of the burners and crossovers for any block­
age caused by foreign matter. Remove any blockage.
8 - Reinstall the burner box assembly using the existing
four screws. Make sure that the burners line up in the
center of the burner ports.
9 - Reconnect the sensor wire and reconnect the 2-pin
plug to the ignitor wiring harness. Reconnect wires to
flame rollout switches.
10 - Reinstall the gas valve manifold assembly. Reconnect
the gas supply line to the gas valve. Reinstall the burn­
er box cover.
11 - Reconnect 2-pin plug to gas valve.
12 - Replace the blower compartment access panel.
13 - Refer to instruction on verifying gas and electrical con­
nections when re-establishing supplies.
14 - Follow lighting instructions to light and operate fur­
nace for 5 minutes to ensure that heat exchanger is
clean and dry and that furnace is operating properly.
15 - Replace heating compartment access panel.
Page 54
Repair Parts List
The following repair parts are available through Lennox dealers. When ordering parts, include the complete furnace model
number listed on the nameplate -- Example: SLP98UH070XV36B. All service must be performed by a licensed profes­
sional installer (or equivalent), service agency, or gas supplier.
Cabinet Parts
Outer access panel
Blower access panel
Top cap
Control Panel Parts
Transformer
Integrated control
Door interlock switch
Circuit breaker
Blower Parts
Blower wheel
Motor
Motor mounting frame
Blower housing cut-off plate
Power choke (1HP only)
Heating Parts
Flame sensor
Heat exchanger assembly
Gas manifold
Combustion air inducer
Gas valve
Main burner cluster
Main burner orifices
Pressure switches
Ignitor
Primary limit control
Flame rollout switches
Page 55
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 Error Code Recall mode. Error Code Recall mode menu options: No change (dis­
playing error history) remains in Error Code Recall mode; solid “b” exits Error Code Recall mode; and solid “c” clears the error history. Must
press button while flashing “c” is displayed to clear error codes.
When the solid “-” is displayed, the control enters the Field Test mode. Field Test mode menu options: Solid “C” starts pressure switch
calibration; blinking “-” exits Field Test 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
Cooling stage (1 second ON, 0.5 second OFF) / 1 or 2 displayed / Pause / cfm
setting displayed / Pause / Repeat codes).
d
Dehumidification mode (1 second ON) / 1 second OFF) / cfm setting displayed /
Pause / Repeat Codes).
h
Variable Capacity Heat (1 second ON, 0.5 second OFF) / % of input rate dis­
played / Pause/ cfm setting / Pause/ Repeat codes.
H
Heat Stage (1 second ON, 0.5 second OFF) / 1 or 2 displayed / Pause / cfm set­
ting displayed / Pause / Repeat codes.
df
Defrost mode.
U
Discharge air temperature
-
Soft disable - Soft disabling is when thermostat finds a device on the BUS that it
does not recognize and the thermostat sends a the device a message to be in soft
disabling mode until properly configured. Two horizontal bars will display.
Steps to follow if the damper control module is displaying
the soft disable code.
1- Confirm proper wiring between all devices
(thermostat, damper control module, indoor and
outdoor).
2- Cycle power to the control that is displaying
the soft disable code.
3- Put the room thermostat through set up.
4- Go to setup / system devices / thermostat /
edit / then push reset.
5- Go to setup / system devices / thermostat /
edit / then push resetAll.
E 105
Device communication problem - No other devices on BUS (Communication
system).
Equipment is unable to communicate. Check for mis wire
and loose connections and check for a high voltage
source of noise close to the system. (welder etc.).
E 110
Low line voltage.
Line Voltage low (Voltage lower than nameplate rating)
Check voltage.
E 113
High line voltage.
Line Voltage High (Voltage higher than nameplate rating)
Check voltage.
E 114
Line voltage frequency out-of-range.
No 60 hertz power (Check voltage and frequency).
E 115
Low 24V - Control will restart if the error recovers.
24 voltage low (Range is 18 to 30 volts) Check voltage.
E 120
Unresponsive device.
Usually caused by delay in outdoor unit responding to
indoor unit poling recycle power, check wiring.
E 124
Active communicating thermostat signal missing for more than 3 minutes.
Equipment lost communication with the thermostat. Check
connections and cycle power on the thermostat.
E 125
Control failed self-check, internal error, failed hardware. Will restart if error
recovers. Integrated furnace control not communicating. Covers hardware errors
(flame sense circuit faults, pin shorts, etc.).
Hardware problem on the control board. Cycle power on
control. Replace if problem prevents service and is
persistent.
E 126
Failed internal control communication between microcontrollers.
Hardware problem on the control board. Cycle power on
control. Replace if problem prevents service and is
persistent.
E 131
Corrupted control parameters (Verify configuration of system).
Reconfigure the system. Replace board if service (heating
/cooling) is unavailable.
E 180
Outdoor air sensor failure - NO error if disconnected. Only shown if shorted or
out-of-range.
Compare outdoor sensor resistance to temperature
resistance charts in installation instructions. Replace if
necessary.
E 200
Hard lockout - Rollout circuit open or previously open.
Correct unit cause of rollout trip or replace flame rollout
switch and test furnace operation.
E 201
Indoor blower communication failure - Unable to communicate with blower motor.
Indoor blower communication failure including power
outage.
Page 56
Integrated Control Diagnostic Codes (continued)
Code
Diagnostic Codes/Status of Equipment
Action Required to Clear and Recover
E 202
Indoor blower motor mis-match - Indoor motor horsepower does not match unit
capacity.
Incorrect furnace size code selected. Check unit size
codes on configuration guide or in installation instructions.
E 203
Appliance capacity / size is NOT programmed. Invalid unit codes refer to
configuration flow chart in installation instructions.
No furnace size code selected. Check unit size codes on
configuration guide or in installation instructions.
E 204
Gas valve mis-wired.
Check operation of gas valve.
E 205
Gas valve control relay contact shorted.
Check operation of gas valve.
E 207
Hot surface ignitor sensed open - Refer to troubleshooting in installation
instruction.
Measure resistance of Hot Surface Ignitor, replace if open
or not within specification.
E 223
Low pressure switch failed open - Refer to troubleshooting in installation
instruction.
Check inches of water column pressure during operation
of low pressure switch on heat call, measure inches of
water column of operating pressure, inspect vent and
combustion air inducer for correct operation and restric­
tion.
E 224
Low pressure switch failed closed - Refer to troubleshooting in installation
instruction.
Check low pressure switch for closed contacts, measure
inches of water column of operating pressure, inspect vent
and combustion air inducer for correct operation and re­
striction.
E 225
High pressure switch failed open - Refer to troubleshooting in installation
instruction.
Check inches of water column pressure of high pressure
switch on heat call, measure inches of water column of
operating pressure, inspect vent and combustion air
inducer for correct operation and restriction.
E 226
High pressure switch failed closed - Refer to troubleshooting in installation
instruction.
Check high pressure switch for closed contacts, measure
inches of water column of operating pressure, inspect vent
and combustion air inducer for correct operation and
restriction.
E 227
Low pressure switch open during trial for ignition or run mode. Refer to trouble­
shooting in installation instruction.
Check inches of water column pressure during operation
of low pressure switch on heat call, measure inches of
water column of operating pressure, inspect vent and
combustion air inducer for correct operation and restric­
tion.
E 228
Unable to perform successful pressure switch calibration.
Retry after 300 seconds. Error counter cleared when exit­
ing lockout, unable to perform pressure switch calibration.
Check vent system and pressure switch wiring
connections.
E 240
Low flame current - Run mode - Refer to troubleshooting in
installation instruction.
Check micro amperes of flame sensor, clean or replace
sensor. Measure voltage of neutral to ground for good unit
ground.
E 241
Flame sensed out of sequence - Flame still present.
Shut off gas, check for gas valve leak.
E 250
Limit switch circuit open - Refer to troubleshooting in installation instruction.
Check why limit is tripping, overfired, low air flow.
E 252
Discharge air temperature too high (gas heat only).
Check temperature rise, air flow and input rate.
E 270
Soft lockout - Exceeded maximum number of retries. No flame current sensed.
Check for gas flow, ignitor lighting burner, flame sensor
current.
E 271
Soft lockout - Exceeded maximum number of retries. Last retry failed due to
the pressure switch opening.
See E 223.
E 272
Soft lockout - Exceeded maximum number of recycles. Last recycle due to the
pressure switch opening.
See E 223 and E 225.
E 273
Soft lockout - Exceeded maximum number of recycles. Last recycle due to
flame failure.
See E 240.
E 274
Soft lockout - Exceeded maximum number of recycles. Last recycle failed due
to the limit circuit opening or limit remained open longer than 3 minutes.
See E 250.
E 275
Soft lockout - Flame sensed out of sequence from code 241 fault. Flame signal
is gone.
See E 241.
E 276
Soft lockout - Exceeded maximum number of calibration retries.
See E 228.
E 290
Ignitor circuit fault - Failed ignitor or triggering circuitry.
See E 207.
E 291
Restricted air flow - Cubic feet per minute is lower than what is needed for
minimum firing rate.
Check for dirty filter, unit air flow restriction, blower
performance.
Page 57
Integrated Control Diagnostic Codes (continued)
Code
Diagnostic Codes/Status of Equipment
Action Required to Clear and Recover
E 292
Indoor blower motor unable to start - Seized bearings, stuck wheel, etc.
Indoor blower motor unable to start (seized
bearing, stuck wheel, etc), replace motor or wheel if
assembly does not operate or meet performance.
E 294
Combustion air inducer motor amp draw is too high.
Check combustion blower bearings, wiring , amperes,
replace if it does not operate or meet performance.
E 295
Indoor blower motor temperature is too high.
Indoor blower motor over temperature (motor
tripped on internal protector), Check motor bear­
ings, amperes. Replace if necessary.
E 310
Discharge error sensor failure - No error if disconnected. Only shown if
shorted or out-of-range.
Discharge air temperature(DATS) out of range,
code is activated during ”Field test mode”.
E 311
Heat rate reduced to match indoor blower air flow. Replace filter or repair
duct restriction.
Furnace blower in cutback mode due to restricted
airflow. Check filter and ductwork. To clear replace
filter if needed or repair/ add ductwork.
E 312
Restricted air flow in cooling or continuous fan mode is lower than cfm
setting.
Restricted airflow - Indoor blower is running at a
reduced cubic feet per minute (Cutback Mode) The variable speed motor has pre-set speed and
torque limiters to protect the motor from damage
caused by operating out of its designed parameters
(0 to 0.8 inches water column total external static
pressure). Check filter and ductwork. To clear re­
place filter if needed or repair/ add ductwork.
E 313
Indoor or outdoor unit capacity mismatch.
Incorrect Indoor /outdoor capacity code selected.
Check for proper configuration in installation instruc­
tions. Alarm is just a warning. The system operation
is not impacted at all and alarm would clear when
Commissioning is exited.
E 331
Global network connection - Communication link problem.
For Future Use.
E 347
No 24 Volt output on Y1 to C with non-communicating outdoor unit.
Y1 relay / Stage 1 failed (Pilot relay contacts did not
close or the relay coil did not energize).
E 348
No 24 Volt output on Y2 to C with non-communicating outdoor unit.
Y2 relay / Stage 2 failed (Pilot relay contacts did not
close or the relay coil did not energize).
E 349
No 24 Volts between R & O with non-communicating outdoor unit (Dual
fuel module required for heat pump application).
Configuration link R to O needs to be cut on control
board.
E 401
LSOM - Compressor ran more than 18 hours in air conditioning mode.
Compressor protector is open. Check for high head
pressure, check compressor supply voltage. Out­
door unit power disconnect is open , compressor
circuit breaker or fuse(s) is open, broken wire or
connector is not making contact. Low or high pres­
sure switch open if present in the system. Compres­
sor contactor has failed to close.
E 402
LSOM - Outdoor unit system pressure trip.
Compressor ran over 18 hours in air conditioning
mode.
E 403
LSOM - Compressor short-cycling (Running less than 4 minutes).
Outdoor unit pressure trip. Check dirty coil, fan mo­
tor, refrigerant charge.
E 404
LSOM - Compressor rotor locked.
Compressor short cycling (Running less than 4 min­
utes).
E 405
LSOM - Compressor open circuit.
Check capacitor, wiring, hard start kit , replace com­
pressor.
E 406
LSOM - Compressor open start circuit.
E 407
LSOM - Compressor open run circuit.
Check compressor for hot (cool down) , check pres­
sures, fan motor etc. Replace compressor if unable
to get circuit to close and compressor to operate.
E 408
LSOM - Compressor contactor is welded.
E 409
LSOM - Compressor low voltage.
Replace contactor.
Page 58
Configuring Unit Size Codes
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)
Yes
To enter Field Test
Mode: push and hold
button
next
to
7-segment LED display
until solid dash symbol
appears.
Release
button.
No
_
Turn room thermostat to OFF
If alarm is present, furnace
control will display error
code. If alarm is not
present solid dash starts
blinking on 7-segment
LED display.
UNIT SIZE
CODE FURNACE MODEL
_
Push and hold button until the solid P
symbol is displayed on the 7-segment
LED. Release button. This mode allows
the user to select a unit size code number
that matches the furnace model size and
capacity.
IMPORTANT: Field replacement controls may
need to be manually configured to validate
furnace unit size code.
Solid P starts
blinking
on
7-Segment LED
−
−
−
P
A
SLP98UHXV-070-36B
b
SLP98UHXV-090-36C
C
SLP98UHXV-090-48C
d
SLP98UHXV-090-60C
E
SLP98UHXV-110-60C
F
SLP98UHXV-135-60D
When the correct unit size code is displayed, release
button. Selected code will flash for 10-second period.
During that period, hold push button until code stops
blinking (disappear for 2 seconds). Integrated control
will store code in memory and will automatically exit
Field Test Mode and reset. (If second period expires
or push button is held less than five seconds, control
will automatically exit Field Test Mode and go into
IDLE mode without storing unit size code. If this
happens, programming function must be repeated).
P
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)
Push and hold button. Integrated control will
display unit size code number for each
furnace model for five seconds.
FINISHED
Page 59
−
−
−
Troubleshooting: Heating Sequence of Operation
IGNITION AND CALL FOR LOW FIRE WITH TWO-STAGE
THERMOSTAT
1
Safety
Check
Verify There
Is No Main Burner
Flame
Limit
Switch
Closed?
Indoor blower OFF After
Heat OFF Delay
(Low Heat Speed)
NO
De-Energize
Gas Valve
Combustion Air
Inducer On
(100% rate
speed)
YES
Indoor Blower
ON (100%)
Error Code
Flashes
Limit
Closes Within 3
Minutes?
Indoor Blower OFF
After Heat OFF Delay
(High Heat Speed)
YES
Rollout
Circuit
Closed?
L
I
G
H
T
NO
De-Energize
Gas Valve
Combustion
Air Inducer
On (100%
rate speed)
Rollout
Circuit
Closes?
Error Code
Flashes
Indoor Blower
ON (70%)
Low
Pressure
Switch
Open?
NO
Error Code Flashes
After 5 Seconds
High
Pressure
Switch
Open?
Low Pressure
Switch Opens
Error Code Flashes
After 5 Seconds
NO
High Pressure
Switch Opens
YES
Soft Lockout:
Error Code
Flashes
YES
1
Combustion Air
Inducer OFF
After Post-Purge
NO
YES
O
F
F
NO
Indoor Blower OFF After
Heat OFF Delay
Hard Lockout:
Error Code
Flashes
flashes
2
YES
Combustion Air
Inducer ON at 70%
Rate Speed
Call
For
Heat?
YES
Low
Pressure Switch
Closed Within 150
Seconds?
NO
Pressure Switch
Calibration
YES
Calibration
Successful?
NO
4
Calibrations
Attempted?
NO
NO
YES
YES
Soft Lockout:
Error Code
Flashes
Call For
Heat
Ends?
NO
Wait
5 minutes
YES
Pre-Purge
15 Seconds
YES
Gas Valve
Energized
C
A
L
L
F
O
R
Indoor
Blower
ON?
Interpurge
(15 Seconds)
Ignitor ON
20 Seconds
Indoor blower OFF
After Heat OFF Delay
NO
Ignition Trial Begins
(Ignitor ON)
1
S
T
Indoor Blower Delay
Timer Started
Flame
Sensed Within
4 seconds?
S
T
A
G
E
NO
1
Gas Valve
De-energized
5th
Unsuccessful
Trial?
NO
Ignitor OFF
YES
Post-Purge
(20Seconds)
Combustion
Air Inducer
OFF
Soft Lockout:
Error Code
Flashes
1
YES
H
E
A
T
Ignitor OFF
Wait For Ignition
Stabilization Delay
Set Target Firing Rate
Based on Thermostat
Signals Present
2
Call For 2nd Stage Heat
OR
1
SOFT LOCKOU T IS RESE T AUTOMATICALLY AFTER ONE HOUR WITH A CALL FOR HE AT ACTIVE,
OR BY CYCLING THE CALL FOR HE AT, OR BY CYCLING POWER TO THE CONTROL.
2
HARD LOCKOU T IS RESE T BY CYCLING POWER TO THE CONTROL.
3A
Call For Heat Satisfied
Page 60
Troubleshooting: Heating Sequence of Operation (Continued)
CALL FOR HIGH FIRE WITH TWO-STAGE THERMOSTAT
2
1
2 Stage
Thermostat
1st Call
for High
Fire?
YES
NO
2nd Stage
Recognition Delay
(30 Seconds)
Combustion Air Inducer ON
(100% Rate Speed)
High
Pressure Switch
Closes Within
10 Seconds?
NO
Increase Combustion
Air Inducer Speed
if Not at 100%
Rate Speed
Error Code
Flashes
YES
Adjust Indoor
Blower to
Appropiate speed
3A
Wait for Call for Heat Satisfied
1
System will always light at 70% even if 2nd stage call for heat is in place
2
If the high pressure switch does not close within 5 attempts, the system
will operate at low fire for the remainder of the call for heat at request
Page 61
Wait 5
Minutes
Troubleshooting: Heating Sequence of Operation (Continued)
CALL FOR HEAT SATISFIED
RUN MODE (TWO-STAGE THERMOSTAT)
FIRST OR SECOND-STAGE CALL FOR HEAT
ALL INPUTS MONITORED (LIMIT, PRESSURE,
CALL FOR HEAT/COOL, FLAME LEVEL).
3A
3B
2nd Stage Heat
NO
2nd Stage
Call for Heat
satisfied?
YES
Combustion Air Inducer
switched to 70% rate speed
Adjust Indoor Blower
to appropiate speed
1st Stage Heat
NO
1st Stage
Call for Heat
satisfied?
YES
Gas valve
De-Energized
Combustion Air Inducer OFF
after 20-Second Post Purge
Indoor Blower OFF
after OFF Delay
1
Wait for Call
Two-Stage
Thermostat
OR
4
Wait for Call
Single-Stage
Thermostat
Page 62
RUN MODE (SINGLE-STAGE THERMOSTAT)
ALL INPUTS MONITORED (LIMIT, PRESSURE,
CALL FOR HEAT/COOL, FLAME LEVEL).
Troubleshooting: Heating Sequence of Operation (Continued)
4
IGNITION AND CALL FOR HEAT WITH SINGLE-STAGE THERMOSTAT
Safety
Check
Verify There
Is No Main Burner
Flame
Limit
Switch
Closed?
Indoor Blower OFF After
Heat OFF Delay
(Low Heat Speed)
NO
De-Energize
Gas Valve
Indoor Blower
ON
(100% Speed)
Error Code
Flashes
Combustion Air
Inducer ON
(100%)
YES
Limit
Closes Within 3 NO
Minutes?
Indoor Blower OFF
After Heat OFF Delay
(High Heat Speed)
YES
Rollout
Circuit
Closed?
L
I
G
H
T
O
F
F
De-Energize
Gas Valve
NO
Combustion Air
Inducer ON
(100%)
YES
Low
Pressure
Switch
Open?
NO
Indoor Blow­
er ON
(70%)
Error Code Flashes
After 5 Seconds
Low Pressure
Switch Opens
Rollout
Circuit
Closes?
Error Code
Flashes
NO
High
Pressure
Switch
Open?
High Pressure
Switch Opens
YES
YES
Combustion Air Inducer
OFF After Post-Purge
Error Code Flashes
After 5 Seconds
NO
Soft Lockout:
Error Code
1
Flashes
Indoor Blower OFF After
Heat OFF Delay
Hard Lockout:
Error Code
2
Flashes
flashes
YES
Combustion Air Inducer ON
at Ignition at 70% rate speed
Call
For
Heat?
YES
Low
Pressure Switch
Closed Within 150
Seconds?
NO
Pressure Switch
Calibration
YES
Calibration
Successful?
NO
4
Calibrations
Attempted?
NO
NO
YES
YES
Call For
Heat
Ends?
Soft Lockout:
Error Code
Flashes
NO
Wait
5 minutes
YES
Pre-Purge
15 Seconds
Indoor
Blower On?
Ignitor ON
20 Seconds
Interpurge
(15 Seconds)
YES
Gas Valve
Energized
Indoor Blower OFF
After Heat OFF Delay
NO
C
A
L
L
F
O
R
H
E
A
T
IgnitionTrial Begins
Ignitor ON
Indoor Blower On
Delay Timer Started
Flame
Sensed Within
4 seconds?
Gas Valve
De-energized
NO
Ignitor OFF
NO
1
5th
Unsuccessful YES
Trial?
Post-Purge
(20 Seconds)
Combustion Air
Inducer OFF
Soft Lockout:
Error Code
Flashes
1
YES
Ignitor OFF
Wait For Ignition
Stabilization Delay
Set to
Low Firing Rate
Move to Mid Firing Rate
and High Firing Rate after
2nd and 3rd Stage Delays
(based on DIP Switch selections)
SOFT LOCKOUT IS RESET AUTOMATICALLY AFTER ONE HOUR WITH A CALL FOR HEAT
1 ACTIVE,OR BY CYCLING THE CALL FOR HEAT, OR BY CYCLING POWER TO THE CON­
TROL.
2 HARD LOCKOUT IS RESET BY CYCLING POWER TO THE CONTROL
3B Call For Heat Satisfied
Page 63
Troubleshooting: Cooling Sequence of Operation
CALL FOR COOLING
5
1st Stage Cooling
Request Received
1
Energize 1st Stage
Cooling Contactor
(Compressor & Fan)
Indoor Blower On
After 2-second delay
Energize Indoor Blower
(Per Ramping Profile)
2
YES
1
2nd Stage
Cooling
Request?
YES
1st Stage
Cooling Request
Still Active?
NO
YES
Energize 2nd Stage
Cooling Contactor
(Compressor & Fan)
Energize Indoor Blower
(High Cooling mode)
2nd Stage
Cooling Request
Still Active?
2
YES
Maintain Indoor Blower
(High Cooling mode)
YES
Energize and
Maintain Indoor Blower at
Low Cooling mode
NO
NO
De-Energize 2nd
Stage Cooling
Contactor
(Compressor & Fan)
1st Stage
Cooling Request
Still Active?
NO
De-Energize 1st
Stage Cooling
Contactor
(Compressor & Fan)
De-Energize Indoor Blower
Per Ramping Profile
2
1
2nd stage cooling operation requires a 2-stage thermostat, a 2-stage cooling system and
on-board link W915 must be be cut. The control will not respond to a 2nd stage cooling
request unless a 1st stage cooling request is active
2
Indoor blower cooling mode and high cooling mode have a specific ON, OFF and speed
ramping profiles. The specific profile is selected using the DIP switches on the control.
Page 64
Troubleshooting: Continuous Fan Sequence of Operation
CONTINUOUS LOW SPEED INDOOR BLOWER SEQUENCE OF OPERATION
6
Call for
Continuous Blower
Indoor Blower On
(Speed Determined by
Dip Switch settings)
Request
for Cooling
Received?
YES
Maintain Indoor
Blower at set speed
5
Go to Call for Cooling
1
Go to Call for Heat -- Two-Stage Thermostat
NO
Request
for Heat
Received?
YES
Maintain Indoor
Blower at set speed
4
NO
Call for Fan
Removed?
OR
NO
Go to Call for Heat -- Single-Stage Thermostat
Maintain Indoor
Blower at set speed
YES
De-Energize
Indoor Blower Per
Ramping Profile
1
1
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 control.
Page 65
Requirements for Commonwealth of Massachusetts
Modifications to NFPA-54, Chapter 10
Revise NFPA-54 section 10.8.3 to add the following re­
quirements:
For all side wall, horizontally vented, gas-fueled equipment
installed in every dwelling, building or structure used in
whole or in part for residential purposes, including those
owned or operated by the Commonwealth and where the
side wall exhaust vent termination is less than seven (7)
feet above the finished grade in the area of the venting, in­
cluding but not limited to decks and porches, the following
requirements shall be satisfied:
1 - INSTALLATION OF CARBON MONOXIDE DETEC­
TORS. At the time of installation of the side wall, hori­
zontally vented, gas-fueled equipment, the installing
plumber or gasfitter shall observe that a hard-wired
carbon monoxide detector with an alarm and battery
backup is installed on the floor level where the gas
equipment is to be installed. In addition, the installing
plumber or gasfitter shall observe that a battery-oper­
ated or hard-wired carbon monoxide detector with an
alarm is installed on each additional level of the dwell­
ing, building or structure served by the side wall, hori­
zontally vented, gas-fueled equipment. It shall be the
responsibility of the property owner to secure the ser­
vices of qualified licensed professionals for the instal­
lation of hard-wired carbon monoxide detectors.
a - In the event that the side wall, horizontally vented,
gas-fueled equipment is installed in a crawl space
or an attic, the hard-wired carbon monoxide detec­
tor with alarm and battery back-up may be installed
on the next adjacent floor level.
b - In the event that the requirements of this subdivi­
sion cannot be met at the time of completion of
installation, the owner shall have a period of thirty
(30) days to comply with the above requirements;
provided, however, that during said thirty (30) day
period, a battery-operated carbon monoxide detec­
tor with an alarm shall be installed.
2 - APPROVED CARBON MONOXIDE DETECTORS.
Each carbon monoxide detector as required in accor­
dance with the above provisions shall comply with
NFPA 720 and be ANSI/UL 2034 listed and IAS certi­
fied.
3 - SIGNAGE. A metal or plastic identification plate shall
be permanently mounted to the exterior of the building
at a minimum height of eight (8) feet above grade di­
rectly in line with the exhaust vent terminal for the hori­
zontally vented, gas-fueled heating appliance or
equipment. The sign shall read, in print size no less
than one-half (1/2) inch in size, “GAS VENT DIRECT­
LY BELOW. KEEP CLEAR OF ALL OBSTRUC­
TIONS.”
4 - INSPECTION. The state or local gas inspector of the
side wall, horizontally vented, gas-fueled equipment
shall not approve the installation unless, upon inspec­
tion, the inspector observes carbon monoxide detec­
tors and signage installed in accordance with the pro­
visions of 248 CMR 5.08(2)(a) 1 through 4.
EXEMPTIONS: The following equipment is exempt
from 24 CMR 5.08(2)(a) 1 through 4:
1 - The equipment listed in Chapter 10 entitled “Equip­
ment Not Required to Be Vented” in the most current
edition of NFPA 54 as adopted by the Board; and
2 - Product Approved side wall, horizontally vented, gasfueled equipment installed in a room or structure sepa­
rate from the dwelling, building or structure used in
whole or in part for residential purposes.
MANUFACTURER REQUIREMENTS GAS EQUIPMENT VENTING SYSTEM PROVIDED.
When the manufacturer of Product Approved side wall,
horizontally vented, gas-fueled equipment provides a vent­
ing system design or venting system components with the
equipment, the instructions provided by the manufacturer
for installation of the equipment and the venting system
shall include:
1 - Detailed instructions for the installation of the venting
system design or the venting system components:
and
2 - A complete parts list for the venting system design or
venting system.
MANUFACTURER REQUIREMENTS GAS EQUIPMENT VENTING SYSTEM NOT PROVIDED.
When the manufacturer of Product Approved side wall,
horizontally vented, gas-fueled equipment does not pro­
vide the parts for venting the flue gases, but identifies “spe­
cial venting systems,” the following requirements shall be
satisfied by the manufacturer:
1 - The referenced “special venting system” instructions
shall be included with the appliance or equipment
installation instructions; and
2
The “special venting systems” shall be Product Ap­
proved by the Board, and the instructions for that sys­
tem shall include a parts list and detailed installation
instructions.
A copy of all installation instructions for all Product
Approved side wall, horizontally vented, gas-fueled
equipment, all venting instructions, all parts lists for
venting instructions, and/or all venting design instruc­
tions shall remain with the appliance or equipment at
the completion of the installation.
Page 66
FOR THE PROVINCE OF ONTARIO, HORIZONTAL SIDEWALL VENT APPLICATIONS ONLY
For exterior horizontal venting applications, the 2” X 1.5”
reducer for 2” venting at the point where the exhaust pipe
exits the structure is not required in direct or non­direct vent
applications in the Province of Ontario. In these applica­
tions, the vent should be oriented such that the exhaust
plume is unobjectionable. If the installation requires more
separation between the flue gases and the building struc­
ture, a reducer may be installed on the exhaust pipe to in­
crease the flue gas velocity.
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