Installation Manual

15
TROUBLESHOOTING INFORMATION: UNITARY DIAGNOSTIC CODES
Digit 3 Digit 2 Digit 1
Air conditioner/heat pump fails to
operate.
Integrated control module
diagnostic/status LED display shows
the indicated code.
BLANK d 3
Configuration Mis-
match
Shared data sent to
integrated control
module does not
match hardware
configuration.
Verify system type
(communicating or
legacy).
Verify shared data
is correct for your
specific model; re-
populate data if
required.
Wire system as
legacy system.
Turn power OFF prior to
repair.
Use memory card for
your specific model.
Insert memory card
BEFORE turning power
ON. Memory card may be
removed after data is
loaded. Turn power OFF
before removing memory
card.
Error code will be
cleared once data is
loaded.
Air conditioner/heat pump fails to
operate.
Integrated control module
diagnostic/status LED display shows
the indicated code.
BLANK d 4
Invalid Memory
Card Data
Shared data on
memory card has
been rejected.
Verify system type
(communicating or
legacy).
Verify shared data
is correct for your
specific model; re-
populate data if
required.
Wire system as
legacy system.
Turn power OFF prior to
repair.
Use memory card for
your specific model.
Insert memory card
BEFORE turning power
ON. Memory card may be
removed after data is
loaded. Turn power OFF
before removing memory
card.
Error code will be
cleared once data is
loaded.
Very long run time.
Four consecutive compressor
protector trips with average run time
between trips greater than 3 hours.
Compressor operating at high speed
and outdoor fan operating at low
speed
Integrated control module
diagnostic/status LED display shows
the indicated code.
BLANK 0 1 Low Side Fault
Low refrigerant
charge.
Restriction in liquid
line.
Indoor blower motor
failure.
Indoor thermostat
set extremely low.
Verify refrigerant
charge; adjust as
needed.
Check for restricted
liquid line; repair/
replace as needed.
Check indoor
blower motor;
repair/replace as
needed.
Check indoor
thermostat setting.
Turn power OFF prior to
repair.
Fault will clear after 3
consecutive normal
cycles.
Fault may be cleared by
cycling 4V AC to control.
Replace with correct
replacement part(s).
Compressor and outdoor fan are off.
Thermostat demand is present.
Integrated control module
diagnostic/status LED display shows
the indicated code.
BLANK 0 1
Low Pressure Cut
Out Trip
Low refrigerant
charge.
Restriction in liquid
line.
Indoor blower motor
failure.
Indoor thermostat set
extremely low.
Verify refrigerant
charge; adjust as
needed.
•Check for restricted
liquid line; repair/
replace as needed.
Check indoor blower
motor; repair/replace
as needed.
Check low pressure
switch; repair/replace
as needed.
Check indoor
thermostat setting.
Turn power OFF prior to
repair.
Replace with correct
replacement part(s).
UNITARY DIAGNOSTIC CODES
Symptoms of Abnormal
Operation
Diagnostic/Status
LED Displav Codes
Fault Description
Possible
Causes
Corrective Actions
Notes &
Cautions