-
1-
Replaces: New
Form: ICP Eng
3-12
Variable Speed, Modulating
Electronic Condensing
Four-Way Multipoise Gas Furnace
*9MAC
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TROUBLESHOOTING GUIDE
INDEX
PAGE
Safety Considerations.............................................................................. 1
Instructions .............................................................................................. 1
Example ................................................................................................... 2
General..................................................................................................... 2
Sequence of Operation ............................................................................ 2
Communicating Control and Modulating Heating......................... 2
Single-Stage Thermostat and Modulating Heating (Adaptive
Mode)...................................................................................... 3
Two-Stage Thermostat and Two-Stage Minimum/Maximum
Heating.................................................................................... 4
Two-Stage Thermostat and Two-Stage Intermediate/Maximum
Heating.................................................................................... 4
Cooling Mode.................................................................................. 5
Single-Speed Cooling ..................................................................... 5
Two-Stage Thermostat and Two-Speed Cooling............................ 5
Dehumidification Mode.................................................................. 5
Super-Dehumidify Mode ................................................................ 5
Continuous-Blower Mode............................................................... 6
Heat Pump Defrost.......................................................................... 6
Component Test .............................................................................. 6
Service/Status Code Instructions............................................................. 7
Start Here................................................................................................. 9
Amber LED On Solid............................................................................10
Improper Cooling Air Flow...................................................................11
Minimum and/or Maximum Heat Temperature Rise Too Low............13
Secondary Voltage Fuse Open ..............................................................14
Status Code 2 - Pressure Switch Did Not Open....................................16
Status Code 3 - Low Pressure Switch Did Not Close or Reopened .....17
Status Code 4 - Limit Circuit Fault .......................................................19
Status Code 5 - Abnormal Flame-Proving Signal.................................21
Status Code 6 - Ignition-Proving Fault .................................................21
Status Code 7 - Limit Circuit Lockout..................................................23
Status Code 8 - Gas Heating Lockout ...................................................24
Status Code 9 - Medium Pressure Switch, High Pressure Switch, or
PSR Relay did not Close or Reopened .........................................24
Status Code 10 - Polarity.......................................................................27
Status Code 1 + 2 - Blower On After Power Up...................................28
Status Code 1 + 5 - Blower Motor Lockout..........................................28
Status Code 2 + 5 - Model Selection or Setup Error ............................29
Status Code 3 + 5 - Gas Valve Fault.....................................................30
Status Code 4 + 1 - Blower Motor Fault...............................................32
Status Code 4 + 2 - Inducer Motor Fault ..............................................34
Status Code 4 + 3 - Low or Medium Pressure Switch Open While
Medium or High Pressure Switch Is Closed.................................36
Status Code 6 + 1 - Ignition Lockout....................................................37
Cleanup and Start-Up Instructions........................................................37
APPENDIX A - Board Layout & Wiring Schematic ...........................38
APPENDIX B - ECM Blower Motor Description & Operation..........40
APPENDIX C - Pressure Check Diagram............................................42
APPENDIX D - Static Pressure Reading Location Diagrams..............43
APPENDIX E - Quick Reference Information..................................... 45
APPENDIX F - Furnace Staging Algorithm ........................................ 46
SAFETY CONSIDERATIONS
Installing and servicing heating equipment can be hazardous due to
gas and electrical components. Only trained and qualified personnel
should install, repair, or service heating equipment.
Untrained personnel can perform basic maintenance functions such
as cleaning coils, or cleaning and replacing filters. All other
operations should be performed by trained service personnel. When
working on heating equipment, observe precautions in literature, on
tags, and on labels attached to or shipped with the unit, and other
safety precautions that may apply.
Follow all safety codes. In the United States, follow all safety codes
including the National Fuel Gas Code (NFGC) NFPA 54-2006/ANSI
Z223.1-2006. In Canada, refer to the National Standard of Canada
Natural Gas and Propane Installation Codes (NSCNGPIC), CSA
B149.1-05.
Wear safety glasses and work gloves. Have a fire extinguisher
available during start-up, adjustment procedures, and service calls.
Recognize safety information. This is the safety-alert symbol
.
When you see this symbol on the furnace and in instructions or
manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, and
CAUTION, and NOTE. The words DANGER, WARNING, and
CAUTION are used with the safety-alert symbol.
DANGER
identifies the most serious hazards which will result in severe
personal injury or death. WARNING signifies hazards which could
result in personal injury or death. CAUTION is used to identify
unsafe practices which may result in minor personal injury, or
product and property damage.
NOTE is used to highlight
suggestions which will result in enhanced installation, reliability, or
operation.
INSTRUCTIONS
This guide uses your expertise and observations to lead you to the
trouble spot as efficiently as possible. This is only intended as a
guide and should not be used blindly. Your experience and expertise
are of high value when troubleshooting this unit. Do not disregard
all of your instincts.
The modulating furnace control was designed with diagnostic
capabilities built in. A AMBER LED is used to flash a status code
which will lead you to one of the sections as listed in the Index.
!
440 08 4001 00
