Installation Manual

18
TROUBLESHOOTING INFORMATION: UNITARY DIAGNOSTIC CODES
Digit 3 Digit 2 Digit 1
• Air conditioner/heat pump
may appear to be operating
normally.
• Compressor protecor may be
open (compressor and outdoor
fan off).
• Integrated control module
diagnostic/status LED display
shows the indicated code.
BLANK H 8
• High Line Voltage • High line voltage
• Correct high line
voltage condition;
contact local utility if
needed.
• Verify unit is
connected to power
supply as specified on
rating plate.
• Turn power OFF prior
to repair.
• Control detects line
voltage greater than 255
VAC.
• Fault will clear if line
voltage decreases
below 255 VAC.
• Air conditioner/heat pump
may appear to be operating
normally.
• Integrated control module
diagnostic/status LED display
shows the indicated code.
BLANK 0 9
• Low Pilot Voltage
• Control detects
secondary voltage
less than 18 VAC.
• Transformer
overloaded.
• Low line voltage.
• Check fuse.
• Correct low secondary
voltage condition.
• Check transformer;
replace if needed.
• Turn power OFF prior
to repair.
• Fault will clear if
secondary voltage rises
above 21 VAC.
• Replace with correct
replacement part(s).
• Compressor is off.
• Integrated control module
diagnostic/status LED display
shows the indicated code.
BLANK P 0
• Comp protector
Open
• No current through
run or start windings.
• Compressor run
winding is open.
• Compressor not
properly wired to
control.
• Faulty Compressor
wiring.
• Failed compressor
run capacitor.
• Faulty run capacitor
wiring.
• Check compressor;
repair/replace as
needed.
• Check wiring
repair/replaced as
needed.
• Check run capacitor;
replace as needed.
• Turn power OFF prior
to repair.
• Fault will clear after 1
normal cycle.
• Must clear fault by
cycling 24 VAC to
control.
• Replace with correct
replacement part(s).
• Air conditioner/heat pump
may appear to be operating
normally.
• Compressor protecor may be
open (compressor and outdoor
fan off).
• Integrated control module
diagnostic/status LED display
shows the indicated code.
BLANK L 8
• Low Line Voltage • Low line voltage.
• Check circuit
breakers and fuses.
• Verify unit is
connected to power
supply as specified on
rating plate.
• Correct low line
voltage condition;
contact local utility if
needed.
• Turn power OFF prior
to repair.
• Control detects line
voltage less than 1 85
VAC.
• Fault will clear if line
voltage increases above
1 85 VAC.
• Air conditioner/heat pump
may appear to be operating
normally.
• Compressor protecor may be
open (compressor and outdoor
fan off).
• Integrated control module
diagnostic/status LED display
shows the indicated code.
BLANK L 8
• No Line Voltage • No line voltage.
• Check circuit
breakers and fuses.
• Verify unit is
connected to power
supply as specified on
rating plate.
• Turn power OFF prior
to repair.
• Control detects line
voltage less than 1 85
VAC.
• Fault will clear if line
voltage increases above
1 85 VAC.
UNIT ARY DIAGNOST IC CODES
Symptoms of Abnormal
Operation
Diagnostic/Status
LED Display Codes
Fault Description Possible Causes Corrective Actions
Notes &
Cautions