Instruction manual
48
■ Furnace fails to
operate.
■ Integrated
control module
LED display
provides “b1”
error code.
b1
■ Integrated
control module
has lost
communication
s with circulator
blower motor.
■ Loose wiring
connection at
circulator motor
control leads.
■ Failed circulator
blower motor.
■ Failed integrated
control module.
■ Tighten or correct
wiring connection.
■ Check circulator
blower motor. Replace
if necessary.
■ Check integrated
control module.
Replace if necessary.
■ Turn off power prior to
repair.
■ Replace circulator
motor with correct
replacement part.
■ Replace integrated
control module with
correct replacement
part.
■ Furnace fails to
operate.
■ Integrated
control module
LED display
provides “b2”
error code.
b2
■ Circulator
blower motor
horse power in
shared data set
does not match
circulator
blower motor
horse power.
■ Incorrect circulator
blower motor in
furnace.
■ Incorrect shared
data set in
integrated control
module.
■ Verify circulator blower
motor horse power is
the same specified for
the specific furnace
model. Replace if
necessary.
■ Verify shared data set
is correct for the
specific model.
Repopulate data using
correct memory card, if
required.
■ Turn off power prior to
repair.
■ Replace motor with
correct replacement
part.
■ Use memory card for
the specific model
■ Insert memory card
before turning on
power. Memory card
may be removed after
data is loaded.
■ Turn off power before
removing memory
card.
■ Error code will be
cleared once shared
data and motor horse
power match.
■ Furnace
operates at
reduced
performance.
■ Airflow
delivered is less
than expected.
■ Integrated
control module
LED display
provides “b3”
error code.
b3
■ Circulator
blower motor is
operating in a
power,
temperature or
speed limiting
condition.
■ Blocked filters.
■ Restrictive
ductwork.
■ Undersized
ductwork.
■ High ambient
temperatures.
■ 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.
■ 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 “b4”
error code.
b4
■ Circulator
blower motor
senses a loss of
rotor control.
■ Circulator
blower motor
senses high
current.
■ Abnormal motor
loading, sudden
change in speed or
torque, sudden
blockage of
furnace air inlet or
outlet.
■ High loading
conditions, blocked
filters, very
restrictive
ductwork,
blockage of
furnace air inlet or
outlet.
■ Check filters, filter
grills/registers, duct
system and furnace air
inlet/outlet for
blockages.
■ Turn off power prior to
repair.
Symptoms of
Abnormal
Operation
Diagnostic/
Staus LED
Code Fault Description Possible Causes Corrective Actions Notes and Cautions