Installation Guide

59
TROUBLESHOOTING CODES
Message Code
• • • •
Furnace fails to operate. Integrated control module LED display provides
b5
error code.
ComfortNet thermostat “Call for Service” icon illuminated. ComfortNet thermostat scrolls “Check Furnace” message.
b5
• Circulator blower
motor fails to start 10 consecutive times.
MTR LCKD
ROTOR
b5 •
• •
Obstruction in circulator blower housing. Seized circulator blower motor bearings. Failed circulator blower motor.
• •
Check circulator blower for obstructions. Remove and repair/replace wheel/motor if necessary. Check circulator blower motor shaft rotation and motor. Replace motor if necessary.
• • •
Turn power OFF prior to repair Replace motor with correct replacement part. Replace wheel with correct replacement part.
• • • •
Furnace fails to operate. Integrated control module LED display provides
b6
error code.
ComfortNet thermostat “Call for Service” icon illuminated. ComfortNet thermostat scrolls “Check Furnace” message.
b6
• •
Circulator blower motor shuts down for over or under voltage condition. Circulator blower motor shuts down due to over temperature condition on power module.
MOTOR
VOLTS
b6 •
• •
High AC line voltage to furnace. Low AC line voltage to furnace. High ambient temperatures.
• •
Check power to furnace. Verify line voltage to furnace is within the range specified on the furnace rating plate. See "Product Description" and
"Location Requirements & Considerations" for furnace installation requirements.
• Turn power OFF prior to repair.
• • • •
Furnace fails to operate. Integrated control module LED display provides
b7
error code.
ComfortNet thermostat “Call for Service” icon illuminated. ComfortNet thermostat scrolls “Check Furnace” message.
b7
• •
Circulator blower motor does not have enough information to operate properly. Motor fails to start 40 consecutive times.
MOTOR
PARAMS
b7 •
•
Error with integrated control module. Motor has a locked rotor condition.
• •
Check integrated control module. Verify control is populated with correct shared data set. See data errors above for details. Check for locked rotor condition (see error code above for details).
• • •
Turn power OFF prior to repair. Replace with correct replacement part(s). Use memory card for the specific model.
• •
Furnace operates at reduced performance. Integrated control module LED display provides
b9
error code.
b9
• Airflow is lower
than demanded.
LOW ID
AIRFLOW
b9 •
• •
Blocked filters. Restrictive ductwork. Undersized ductwork.
• • •
Check filters for blockage. Clean filters or remove obstruction. Check ductwork for blockage. Remove obstruction. Verify all registers are fully open. Verify ductwork is appropriately sized for system. Resize/replace ductwork if necessary.
• Turn power OFF prior to repair.
Diagnostic
& Status
LED Codes
Fault
Description
Symptoms of Abnormal Operation
(Non-communicating
& ComfortNet™ Thermostat)
ComfortNet
Thermostat Only
Possible Causes Corrective Actions Notes & Cautions