2
IMPORTANT SAFETY INFORMATION ......................3
REQUIREMENTS & CODES ......................................3
Combustion Air Quality ........................................... 4
Clearances to Combustible Materials ..................... 4
Heating Load ..........................................................4
Installation in a Garage ...........................................5
Operation of Furnace During Construction .............5
COMBUSTION AIR & VENTING REQUIREMENTS ...6
Important Information ..............................................7
Installation in a ConďŹned Space .............................7
Air From Inside ....................................................7
Outdoor Air from a Crawl Space or
Vented Attic ......................................................... 7
Outdoor Air Using Vertical Ducts .........................7
Outdoor Air Using Horizontal Ducts ....................7
Air Directly Through an Exterior Wall ..................8
Alternate Method of Providing Air from
Outside ................................................................9
Installation in an UnconďŹned Space .......................9
Category I Venting ..................................................9
Horizontal Venting ................................................. 10
Flexible Vent Systems .......................................... 10
CIRCULATING AIR REQUIREMENTS ..................... 11
Plenums & Air Ducts ............................................. 11
Return Air Connections ........................................ 11
UpďŹow / Horizontal Furnaces ............................ 11
DownďŹow Furnaces ........................................... 12
Supply Air Connections ........................................ 12
Acoustical Treatments .......................................... 12
FURNACE INSTALLATION ...................................... 12
About the Furnace ................................................ 12
Before you Install the Furnace .............................. 12
Locating the Furnace ............................................ 13
UpďŹow Furnaces ................................................... 13
Horizontal Furnaces .............................................. 13
DownďŹow Furnaces .............................................. 14
Installation on a Concrete Slab ......................... 14
Pressure Switches ................................................ 15
Bottom Panel Removal ......................................... 15
Alternate Bottom Panel Removal ...................... 15
GAS SUPPLY & PIPING ........................................... 16
Leak Check .......................................................... 16
High-Altitude Application ...................................... 18
Conversion to LP / Propane .................................. 19
ELECTRICAL WIRING .............................................. 19
Line Voltage Wiring ............................................... 19
Grounding ............................................................. 20
Thermostat / Low Voltage Connections ................ 20
Single Stage AC & Single Stage Heat
Thermostat ........................................................ 21
Single Stage AC & Two - Stage Heat
Thermostat ........................................................ 21
Two - Stage AC & Two - Stage Heat
Thermostat ........................................................ 21
Autostaging for Single Stage Thermostats ........... 21
Autostaging for Two-Stage Thermostats .............. 22
Blower Speed ConďŹguration ................................. 22
Fixed Speed Blowers ............................................ 22
Variable Speed Blowers ....................................... 22
DehumidiďŹcation Options ..................................... 22
Heat Anticipator .................................................... 23
START-UP & ADJUSTMENTS .................................. 23
Pre-Start Checklist ............................................... 23
Start-Up Procedures ............................................. 23
Verifying & Adjusting Input Rate ........................... 23
Verifying & Adjusting Temperature Rise ............... 23
Verifying Burner Operation ................................... 24
Verify Operation of the Supply Air Limit Switch .... 24
OPERATING SEQUENCE ........................................ 25
Heating Cycle ....................................................... 25
Cooling Cycle ....................................................... 25
Fan Mode .............................................................. 25
MAINTENANCE ........................................................ 26
FIGURES & TABLES ................................................ 28
Figure 21 - Furnace Dimensions ....................... 28
AirďŹow Data .......................................................... 29
Table 3 - Heating / Cooling AirďŹows &
Temperature Rises - Fixed
Speed ......29
Table 4 -
Nominal CFM & Temperature Rises -
Variable Speed ...................................31
Table 5 -
Nominal Cooling / Heat Pump CFM -
Variable Speed ...................................32
Electrical Information ............................................ 33
Figure 22 - Two-Stage Fixed Speed Motor
Control Board .................................. 33
Figure 23 - Two-Stage Variable Speed
Motor Control Board ....................... 33
Figure 24 - Two-Stage Furnace Control Board .. 33
Figure 25 - Wiring Diagram - 2 Stage Fixed
Speed UpďŹow/Horiz. Furnaces ....... 34
Figure 26 - Wiring Diagram - 2 Stage Fixed
Speed DownďŹow Furnaces ............. 35
Figure 27 - Wiring Diagram - 2 Stage Variable
Speed UpďŹow/Horiz. Furnaces ....... 36
Figure 28 - Wiring Diagram - 2 Stage Variable
Speed DownďŹow Furnaces ............. 37
Gas Information .................................................... 38
Table 6 - Gas Flow Rates .................................. 38
Table 7 - Gas Pipe Capacities ...........................38
Table 8 - High Altitude Deration Chart for
Propane Gas .................................... 39
Table 9 - Natural Gas Heating Values ............... 39
Table 10 - High Altitude Deration Chart for
Nat. Gas - High Heating Value .......... 40
Table 11 - High Altitude Deration Chart for
Nat. Gas - Low Heating Value .......... 40
Troubleshooting .................................................... 41
Table 12 - Furnace Control Board Faults .......... 41
Table 13 - Motor Control Board Faults ............... 41
Furnace Components ........................................... 41
Figure 29 - Component Locations ..................... 42
INSTALLATION / PERFORMANCE CHECKLIST .... 44
TABLE OF CONTENTS