Page 1
INSTALLATION
INSTRUCTIONS
SLP98UHV
507026-02
05/2016
Superseds 507026-01
 WARNING
Improper installation, adjustment, alteration, service 
or maintenance can cause property damage, personal 
injury or loss of life. Installation and service must  be 
performed by a licensed professional HVAC installer or 
equivalent, service agency, or the gas supplier.
THIS MANUAL MUST BE LEFT WITH THE 
HOMEOWNER FOR FUTURE REFERENCE
 This is a safety alert symbol and should never be 
ignored. When you see this symbol on labels or in man-
uals, be alert to the potential for personal injury or death.
 CAUTION
As with any mechanical equipment, contact with sharp 
sheet metal edges can result in personal injury. Take 
care while handling this equipment and wear gloves and 
protective clothing.
 NOTICE
A thermostat is not included and must be ordered 
separately.
•  The Lennox iComfort Wi-Fi
®
 thermostat must be used 
in communicating applications.
 • In non-communicating applications, the Lennox 
ComfortSense
® 
7500 thermostat may be used, as well 
as other non-communicating thermostats.
In all cases, setup is critical to ensure proper system 
operation.
Field wiring for both communicating and non-
communicating applications is illustrated in diagrams, 
which begin on Page 25.
© 2016 Lennox Industries Inc. 
Dallas, Texas  USA
DAVE LENNOX SIGNATURE®
COLLECTION GAS FURNACES
UP/FLOW HORIZONTAL AIR DISCHARGE
Contents
Unit Dimensions .............................................................2
Parts Arrangement..........................................................3
SLP98UHV Gas Furnace ...............................................4
Shipping and Packing List ..............................................4
Safety Information ..........................................................4
Use of Furnace as Cinstruction Heater ..........................5
General ...........................................................................6
Installation - Setting Equipment ......................................6
Filters ............................................................................10
Duct System ................................................................. 11
Pipe Fittings Specications........................................... 11
Joint Cementing Procedure .......................................... 12
Venting Practices ..........................................................13
Vent Pipe Guidelines ....................................................13
Gas Piping ....................................................................27
Electrical .......................................................................30
Integrated Control .........................................................38
Unit Start-Up .................................................................47
Turning Off Gas to Unit ................................................. 48
Failure To Operate ........................................................48
Unit Start-Up .................................................................48
Gas Flow ......................................................................48
Operating Pressure Signal Measurement ....................48
Proper Combustion.......................................................50
High Altitude Information ..............................................50
Other Unit Adjustments.................................................50
Heating Sequence of Operation ...................................51
Service..........................................................................53
Repair Parts List ...........................................................55
Integrated Control Diagnostic Codes............................56
Conguring Unit Size Codes ........................................59
Troubleshooting: Heating Sequence of Operation .......60