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Table 9 – Troubleshooting Chart--Heat Pump Operation
SYMPTOM CAUSE REMEDY
Compressor and outdoor fan
will not start
Power failure Call power company
Fuse blown or circuit breaker tripped Replace fuse or reset circuit breaker
Defective contactor, transformer, HP/AC control board,
or high--pressure, loss--of--charge or low--pressure
switch
Replace component
Insufficient line voltage Determine cause and correct
Incorrect or faulty wiring Check wiring diagram and rewire correctly
User Interface setting too low/too high ResetUIsetting
DO NOT bypass this compressor time
delay–wait for 5 minutes until time--delay
relay is de--energized
Units have a 5--minute time delay
Compressor will not start but outdoor fan
runs
Faulty wiring or circuit
Loose connections in compressor
Check wiring and repair or replace
Compressor motor burned out, seized, or Determine cause
internal overload open Replace compressor
Defective run capacitor, overload, or PTC (positive
temperature coefficient) thermistor
Determine cause and replace
Low input voltage Determine cause and correct
Compressor cycles (other than normally satis-
fying) cooling/heating calls
Refrigerant overcharge or undercharge
Recover refrigerant, evacuate system, and re-
charge to capacities shown on rating plate
Defective compressor Replace and determine cause
Insufficient line voltage Determine cause and correct
Blocked outdoor coil Determine cause and correct
Defective run/start capacitor, overload or start relay Determine cause and replace
Faulty outdoor fan motor or capacitor Replace
Damaged reversing valve Determine cause and correct
Restriction in refrigerant system Locate restriction and remove
Compressor operates continuously
Dirty air filter Replace filter
Unit undersized for load Decrease load or increase unit size
UI temperature set too low/too high ResetUIsetting
Low refrigerant charge Locate leak, repair, and recharge
Air in system
Recover refrigerant, evacuate system, and re-
charge
Outdoor coil dirty or restricted Clean coil or remove restriction
Excessive head pressure
Dirty air filter Replace filter
Dirty indoor or outdoor coil Clean coil
Refrigerant overcharged Recover excess refrigerant
Air in system
Recover refrigerant, evacuate system, and re-
charge
(Heat) Indoor air restricted or recirculating Determine cause and correct
Indoor or outdoor air restricted or air short--cycling Determine cause and correct
Continued next p age.
Table 10 – Troubleshooting Chart--Heat Pump Operation
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
(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
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 ResetUIsetting
(Cool) Outdoor ambient below 55°F(13°C) Verify low--ambient cooling enabled in UI
Filter drier restricted Replace
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
48XT-- A
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