Installation Guide
2
TABLE OF CONTENTS
IMPORTANT SAFETY INFORMATION ..................... 3
CODES & REQUIREMENTS ..................................... 4
Combustion Air Quality............................................ 5
Heating Load ........................................................... 5
Operation of Furnace During Construction ............. 6
Installation in a Garage............................................ 6
Clearances to Combustible Materials...................... 6
COMBUSTION AIR & VENTING REQUIREMENTS . 7
Direct Vent Furnaces............................................... 8
Conventional Vent Systems - Confined Spaces...... 8
Air From Inside..................................................... 9
Outdoor Air from a Crawl Space or Vented Attic .. 9
Outdoor Air Using Vertical Ducts.......................... 9
Outdoor Air Using Horizontal Ducts ..................... 9
Air Directly Through An Exterior Wall................... 9
Alternate Method of Providing Air from Outside... 10
Conventional Vent Systems - Unconfined Spaces.. 10
Category IV Venting ................................................ 10
Vent Pipe Material ................................................ 11
Vent Pipe Length & Diameter............................... 11
Vent Pipe Installation............................................ 12
Outdoor Terminations - Horizontal Venting........... 12
Outdoor Terminations - Vertical Venting ............... 13
Vent Freezing Protection ...................................... 13
Existing Installations ............................................ 14
Condensate Disposal .............................................. 14
CIRCULATING AIR REQUIREMENTS...................... 14
Plenums & Air Ducts................................................ 14
Return Air Connections ........................................... 15
Upflow & Horizontal Furnaces ............................. 15
Downflow Furnaces ............................................. 15
Supply Air Connections........................................... 15
Acoustical Treatments ............................................. 15
FURNACE INSTALLATION ....................................... 16
General Requirements ............................................ 16
Upflow Furnaces...................................................... 16
Horizontal Furnaces ................................................ 16
Special Instructions for SC038-23A Furnaces ..... 16
Downflow Furnaces ................................................. 17
Installation on a Concrete Slab ............................ 17
Inducer & Venting Options....................................... 18
Inducer Assembly Rotation .................................. 18
Pressure Switch Tubing........................................ 18
Alternate Pressure Switch Location..................... 18
Accessories ............................................................. 20
Finish Flange ....................................................... 20
Rubber Grommets................................................ 20
PVC Components ................................................ 21
Typical Orientation ........................................... 21
Alternate Orientation ........................................ 21
Optional PVC Pipe Installation............................. 21
Condensate Drain Lines....................................... 21
Bottom Panel Removal............................................ 22
Alternate Bottom Panel Removal ............................ 22
GAS SUPPLY & PIPING ............................................ 23
Leak Check.............................................................. 23
High Altitude Application (Natural Gas Only) .......... 24
Converting from Natural Gas to LP / Propane......... 27
ELECTRICAL WIRING............................................... 27
Line Voltage Wiring ................................................. 28
Grounding................................................................ 28
Thermostat / Low Voltage Connections .................. 29
Heat Anticipator....................................................... 29
Twinning................................................................... 29
34!2450!$*534-%.43................................... 30
Pre-Start Check List ................................................ 30
Start-up Procedures ................................................ 30
Verifying & Adjusting Input Rate.............................. 30
Verifying & Adjusting Temperature Rise.................. 31
Verifying Burner Operation...................................... 31
Verifying Operation of the Supply Air Limit Switch.. 31
OPERATING SEQUENCE ......................................... 31
Heating Cycle .......................................................... 31
Cooling Cycle .......................................................... 31
Fan Mode ................................................................ 31
MAINTENANCE ......................................................... 32