Installation Guide

2
IMPORTANT SAFETY INFORMATION .......................3
CODES & REQUIREMENTS .......................................4
Combustion Air Quality ..............................................5
Heating Load .............................................................5
Installation in a Garage ..............................................6
Clearances to Combustible Materials ........................6
Operation of Furnace During Construction ................6
COMBUSTION AIR & VENTING REQUIREMENTS ....7
Important Information ................................................8
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 ......................................... 24
Conversion to LP / Propane .................................... 27
ELECTRICAL WIRING ...............................................27
Line Voltage Wiring ................................................. 28
Grounding ................................................................28
Thermostat / Low Voltage Connections ..................29
Heat Anticipator ...................................................29
Twinning ............................................................... 29
START-UP&ADJUSTMENTS ................................... 30
Pre-Start Checklist .................................................. 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
TABLE OF CONTENTS