Table 7—Troubleshooting Chart (Cont’d)
SYMPTOM
CAUSE
REMEDY
Head pressure too low
Low refrigerant charge
Check for leaks, repair and recharge
Restriction in liquid tube
Remove restriction
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
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
Filter-drier restricted
Replace
Compressor runs but outdoor fan does not
NC (normally closed) contacts on defrost board
open
Check condition of relay on board
Replace if necessary
IFM does not run
Blower wheel not secured to shaft
Properly tighten blower wheel to shaft
Insufficient voltage at motor
Determine cause and correct
Power connectors not properly sealed
Connectors should snap easily; do not force
IFM operation is intermittent
Water dripping into motor
Verify proper drip loops in connector wires
Connectors not firmly sealed
Gently pull wires individually to be sure they are
crimped into the housing
IFM–Indoor Fan Motor
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