49
■
Furnace fails to
operate.
■
Integrated
control module
LED display
provides “b5”
error code.
b5
■
Circulator
blower motor
fails to start 10
consecutive
times.
■
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 off power 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.
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.
■
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 and
Considerations” for
furnace installation
requirements.
■
Turn off power prior to
repair.
■
Furnace fails to
operate.
■
Integrated
control module
LED display
provides “b7”
error code.
b7
■
Circulator
blower motor
does not have
enough
information to
operate
properly.
■
Motor fails to
start 40
consecutive
times.
■
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 off power prior to
repair.
■
Replace with correct
replacement part(s).
■
Use memory card for
the specific model.
■
Furnace
operates at
reduced
performance or
operates on low
stage when
high stage is
expected.
■
Integrated
control module
LED display
provides “b9”
error code.
b9
■
Airflow is lower
than demanded.
■
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 off power prior to
repair.
Symptoms of
Abnormal
Operation
Diagnostic/
Staus LED
Code
Fault Description Possible Causes
Corrective Actions
Notes and Cautions