Installation Manual

16
TROUBLESHOOTING INFORMATION: UNITARY DIAGNOSTIC CODES
Digit3 Digit2 Digit 1
• Compressor and outdoor fan are off.
• Low pressure switch trip 3 times within
same thermostat demand.
• Thermostat demand is present.
• Intergrated control module
diagnostic/status LED display shows the
indicated code.
BLANK L 1
• Low Pressure Cut Out
Lockout (3 Trips)
• 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.
• Must clear fault by
cycling 24 VAC to control.
• Replace with correct
replacement part(s).
• Four consecutive compressor protector
trips with average run time between trips
greater than 1 minute and less than 1 5
minutes.
• Low pressure and high pressure
switches are closed.
• Intergrated control module
diagnostic/status LED display shows the
indicated code.
BLANK 0 2 • High Side Fault
• Blocked condenser
coil.
• Outdoor fan not
running.
• Check and clean
condenser coil.
• Check outdoor fan
motor; repair/replace as
needed.
• Check outdoor fan
motor wiring;
repair/replace as
needed.
• Check outdoor fan
motor capacitor;
replace as needed.
• Turn power OFF prior to
repair.
• Fault will clear after 4
consecutive normal cycles.
• Fault may be cleared by
cycling 24 VAC to control.
• Replace with correct
replacement part(s)
• Compressor and outdoor fan are off.
• Thermostat demand is present.
• Intergrated control module
diagnostic/status LED display shows the
indicated code.
BLANK 0 2 • High Pressure Cut Out
Trip
• Blocked condenser
coil.
• Outdoor fan not
running.
• Check and clean
condenser coil.
• Check outdoor fan
motor; repair/replace as
needed.
• Check outdoor fan
motor wiring;
repair/replace as
needed.
• Check outdoor fan
motor capacitor;
replace as needed.
• Turn power OFF prior to
repair.
• Replace with correct
replacement part(s).
• Compressor and outdoor fan are off.
• Low pressure switch trip 3 times within
same thermostat demand.
• Thermostat demand is present.
• Intergrated control module
diagnostic/status LED display shows the
indicated code.
BLANK L 2
• High Pressure Cut Out
Lockout (3 Trips)
• Blocked condenser
coil.
• Outdoor fan not
running.
• Check and clean
condenser coil.
• Check outdoor fan
motor; repair/replace as
needed.
• Check outdoor fan
motor wiring;
repair/replace as
needed.
• Check outdoor fan
motor capacitor;
replace as needed.
•Turn power OFF prior to
repair.
•Must clear fault by cycling
24 VAC to control.
•Replace with correct
replacement part(s).
UNITARY DIAGNOSTIC CODES
Symptoms of Abnormal Operation
Diagnostic/Status
LED Display Codes
Fault
Description
Possible Causes Corrective Actions Notes & Cautions