COOLING AND HEATING TROUBLESHOOTING CHART (cont)
SYMPTOM
CAUSE
REMEDY
Excessive suction
pressure.
(Heat) Outdoor coil frosted
Move timer on control board to 30 minutes
between defrost cycles.
(Cool) High heat load
Check for source and eliminate.
Compressor valves leaking
Replace compressor.
Reversing valve hung up or leaking internally
Replace valve.
Refrigerant overcharged
Recover excess refrigerant.
Suction pressure too
low.
(Cool) Dirty air filter
Replace filter.
(Heat) Outdoor coil frosted
Move timer on control board to 30 minutes
between defrost cycles.
Low refrigerant charge
Check for leaks, repair and recharge.
Metering device or low side restricted
Remove source of restriction.
(Cool) Insufficient coil airflow
Increase air quantity. Check filter — replace if
necessary.
(Cool) Temperature too low in conditioned area
Reset thermostat.
(Cool) Outdoor ambient below 40 F
Install low-ambient kit.
Field-installed filter-drier restricted
Replace.
Compressor runs but
outdoor fan does not.
Normally closed contacts on defrost board open
Check condition of relay on board. Replace if necessary.
23
