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Table 9 – Troubleshooting Chart -- Cooling
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, trans former, control relay, o r high--
pressure, loss--of--charge or low--pressure switch
Replace component
Insufficient line voltage Determine cause and correct
Incorrect or faulty wi ring Check wiring di agram and rewire correctly
UI setting too low/too high ResetUIsetting
DO NOT bypass this compressor time
delay–wait for 5 minutes unti l time--delay
relay is d e--energized
Units have a 5--minute time delay
Compressor will not start but condenser 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 (20 percent low) Determine cause and correct
Compressor cycles (other than normally sat-
isfying) cooling/heating calls
Refrigerant overchar ge 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 caus e and replace
Faulty outdoor fan motor or capacitor Replace
Restriction in refrigerant system Locate restriction and remove
Compressor operates continuously
Dirt y air filter Replace fi lter
Unit undersized for load Decreas e load or increase unit size
UI temperature set too low 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
Dirt y air filter Replace fi lter
Dirty indoor or outdoor coil Clean coil
Refrigerant overcharged Recover excess refrigerant
Air in system
Recover refrigerant, evacuate system, and re-
charge
Indoor or outdoor air restricted or air short--cycling Determine cause and correct
Head pressure too low
Low refrigerant charge Check for leaks, repair and recharge
Restriction in liqui d tube Remove restriction
Excessive suction pressure
High heat load Check for source and eliminate
Revers ing valve hung up or leaking internally Replace valve
Refrigerant overcharged Recover excess refrigerant
Suction pressure too low
Dirt y air filter Repl ace filter
Low refrigerant charge Check for leaks, repair and recharge
Metering device or low side r estricted Remove source of restriction
Insu f ficient coil airflo w Check filter–replace if necessary
Temperature too low in conditioned area ResetUIsetting
Outdoor ambient below 55°F(13°C) Verify low--ambient cooling enabled in UI
Filter drier re stricted Replace
IFM does not run
Blower wheel not secured to shaft Properly tighten blower wheel to shaft
Insufficient vol tage 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 seal ed
Gently pull wires individually to be sure they are
crimped into the housing
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