Installations Instructions
60
TROUBLESHOOTING CODES
Message Code
•
•
•
•
Fu rn ace f ails 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
ROT OR
b5 •
•
•
Obstruction in circulator blower
housing.
Seized circulator blower motor
bearings.
Failed circulator blower motor.
•
•
Check circulator blower f or
obstructions. Remove and
repair/replace wheel/motor if necessary.
Check circulator blower motor shaf t
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.
•
•
•
•
Fu rn ace f ails 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 f or 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 f urnace.
Low AC line voltage to f urnace.
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.
•
•
•
•
Fu rn ace f ails 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 f ilters for blockage. Clean filters
or remove obstruction .
Check ductwork for blockage. Remove
obstruction. Verif y 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™ T hermostat)
ComfortNet
Thermostat Only
Possible Causes Corrective Actions Notes & Cautions