Page 1
01/10
*2P0110*
506435−01
*P506435-01*
2009 Lennox Industries Inc.
Dallas, Texas, USA
DOWNFLOW
HORIZONTAL RIGHT
HORIZONTAL LEFT
UPFLOW
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.
INSTALLATION
INSTRUCTIONS
G71MPP
DAVE LENNOX SIGNATURE
®
COLLECTION GAS FURNACE
MULT−POSITION VARIABLE CAPACITY
506435−01
01/2010
Supersedes 12/2009
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.
NOTICE
A thermostat is not included and must be ordered
separately.
The Lennox icomfort Touch thermostat must be
used in communicating applications.
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 sys-
tem operation.
Field wiring for both communicating and non−com-
municating applications is illustrated in diagrams,
which begin on Page 30.
Table of Contents
Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G71MPP Parts Arrangement 3. . . . . . . . . . . . . . . . . . . . . . . . . .
Shipping and Packing List 4. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Information 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use of Furnace as Construction Heater 5. . . . . . . . . . . . . . . . .
General 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation − Setting Equipment 6. . . . . . . . . . . . . . . . . . . . . . . .
Filters 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Duct System 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pipe & Fittings Specifications 13. . . . . . . . . . . . . . . . . . . . . . . . .
Vent Pipe Sizing Worksheet 15. . . . . . . . . . . . . . . . . . . . . . . . . .
Vent Piping Guidelines 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Joint Cementing Procedure 17. . . . . . . . . . . . . . . . . . . . . . . . . .
Venting Practices 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Piping 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Integrated Control 36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Motor Performance 43. . . . . . . . . . . . . . . . . . . . . . . . . .
Unit Start−Up 54. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Pressure Measurement 55. . . . . . . . . . . . . . . . . . . . . . . . . .
High Altitude Information 56. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other Unit Adjustments 56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heating Sequence of Operation 57. . . . . . . . . . . . . . . . . . . . . .
Service 58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Integrated Control Diagnostic Codes 61. . . . . . . . . . . . . . . . . .
Configuring Unit Size Codes 64. . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting 65. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair Parts List 71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Start−Up & Performance Check List 71. . . . . . . . . . . . . . . . . . .
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