Installation Manual

13
TROUBLESHOOTING INFORMATION: UNITARY DIAGNOSTIC CODES
Digit3 Digit2 Digit 1
• Integrated control module
diagnostic/status LED display shows
the indicated code.
BLANK A 2
• Outdoor air temp
sensor fault
• Shorted sensor.
• Open sensor.
• Sensor disconnected.
• Sensor out of range.
• Check sensor
connection.
• Replace open/ shorted
sensor.
• Turn power OFF prior to repair.
• Replace with correct
replacement part.
• Heat pump fails to operate in
heating mode.
• Integrated control module
diagnostic/status LED display shows
the indicated code.
BLANK A 3
• Outdoor coil temp
sensor fault
• Shorted sensor
• Open sensor.
• Sensor. disconnected.
• Sensor out of range.
• Check sensor
connection.
• Replace open/ shorted
sensor.
• Turn power OFF prior to repair.
• Replace with correct
replacement part.
• Air conditioner/heat pump fails to
operate.
• Integrated control module
diagnostic/status LED display shows
the
indicated code.
BLANK E 5 • Open fuse
• Short in low voltage
wiring.
• Locate and correct short
in low voltage wiring.
• Turn power OFF prior to repair.
• Replace fuse with
3-amp automotive type.
• Air conditioner/heat pump fails to
operate.
• Integrated control module
diagnostic/status LED display shows
the
indicated code.
BLANK E E • Board mis- operation
• Compressor relay
contacts welded.
• Replace control.
• Turn power OFF prior to repair
• Replace with correct
replacement part.
• Air conditioner/heat pump fails to
operate.
• Integrated control module
diagnostic/status LED display shows
the indicated code.
BLANK b 0
• Circulator
blower motor is not
running when it
should be running.
• Indoor bIower motor
problem.
• Communications error
between indoor and
outdoor unit.
• Check indoor bIower
motor.
• Check indoor bIower
motor wiring.
• Check indoor unit
control.
• Repair/ replace any
faulty wiring.
• Repair/ replace
indoor bIower motor or
control.
• Turn power OFF prior to repair.
• Replace with correct
replacement part.
• Air conditioner/heat
pump operates at reduced
performance.
• Air conditioner/heat pump
operating at low stage when expected
to operate at high stage.
• Integrated control module
diagnostic/status LED display shows
the indicated code.
BLANK b 9
• Air flow is lower
than demanded
• Indoor bIower motor
problem
• Blocked filters .
• Restrictive/ undersized
ductwork
• Indoor/ outdoor unit
miss-match.
• Check indoor blower
motor.
• Check Filters
clean/replace as needed.
• Check ductwork, resize
as needed.
• Verify indoor and
outdoor units are
properly matched.
• Turn power OFF prior to repair.
• Replace with correct
replacement part. See
specification sheets for airflow
requirements and maximum
external static pressure.
• See specification sheets for
approved system matches.
SYSTEM TROUBLESHOOTING
UNITARY DIAGNOSTIC CODES
Symptoms of Abnormal
Operation
Diagnostic/Status LED
Display Codes
Fault Description Possible Causes
Corrective
Actions
Notes &
Cautions