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Table 12 – Troubleshooting Guide -- Cooling or Heat Pump Heating Mode
SYMPTOM CAUSE REMEDY
Compressorand Outdoorfanwillnot
start.
Power F ailure Call power company.
Fuse blown or circuit breaker tripped Replacefuseorresetcircuitbreaker.
Defective thermostat, contactor, transformer,or control
relay
Replace component.
Insufficientline voltage Determinecause andcorrect.
Incorrect or faulty wiring Check wiring diagram and rewire correctly .
Thermostat setting too high Lower thermostat s etting below room temperature.
Compressor willnot start but Outdoor
fan runs.
Faultywiringor loose connectionsin compressor circuit Check wiring and repair or replace.
Compressor motor burned out,seized,or internal over-
loadopen
Determine cause Replace compressor.
Defective run/start capacitor, overload, startrelay Determine cause andr eplace.
Onelegof3---phasepowerdead
Replacef useor reset circuitbreaker.D etermine
cause.
Three---phase scrollcompressor makes
excessive noise,and there may
be alow pressure differential.
Scroll compressoris rotatingin the wrong direction
Correct the direction of rotation by reversing the
3---phase power leads tothe unit.
Compressor cycles (other thannormally
satisfying thermostat).
Refrigerantoverchargeor undercharge
Recover refrigerant, evacuatesystem, andrecharge
to capacities shown on nameplate.
Defective compressor Replace and determine cause.
Insufficientline voltage Determinecause andcorrect.
Blocked Outdoor Determinecause andcorrect.
Defective run/start capacitor, overloador startrelay Determine causean d replace.
Defectivethermostat Replace thermostat.
Faulty Outdoor---fan motor orcapacitor Replace.
Damaged reversing valve Determinecause andcorrect
Restriction in refrigerant system Locate restriction andremove.
Compressor operates continuously.
Dirty air filter Replace filter.
Unitundersizedfor load Decrease load or increase unit size.
Thermostat set too low Reset thermostat.
Low refrigerantcharge L ocate leak,r epair, and recharge.
Mechanical damage in compressor. Replace compressor.
Air in system Recover refrigerant, evacuate system,and recharge.
Frostedcoil with incorrect defrost operation
Check defrost time settings, Reset as necessary
Check defrost temperature switch, Replace asnec-
essary
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 excessrefrigerant.
Air in system Recover refrigerant, evacuate system,and recharge.
Indoor or Outdoor air restricted or air short---cycling Determinecause andcorrect.
Head pressure too low.
Low refrigerantcharge Check for leaks,repair, and recharge.
Compressor IPR leaking Replace compressor.
Restrictioninliquidtube Remove restriction.
Excessive suction pressure.
High heat load Checkfor sourceand eliminate.
Compressor IPR leaking Replace compressor.
Refrigerant overcharged Recover excessrefrigerant.
Reversingvalvehung upor leaking internally Replace valve
Suction pressure too low.
Dirty air filter Replace Filter.
Low refrigerantcharge Check for leaks,repair, and recharge.
Metering device or low si d e restricted Remove source of restriction.
InsufficientIndoor airflow
Increase air quantity. Check filter — replace if neces-
sary.
Temperature too low in conditioned area Reset thermostat.
Outdoor ambient below 55°F (12.8°C) Install low---ambient kit.
Field---installed filter---drier restricted Replace.
(Heat) Outdoor coil frosted
Move timer on control board to 30 minutes between
defrost cycles
Compressor runs but outdoor fan does
not
NC (normally closed)contacts on defrostboard open
Check condition of relay on board Replace if neces-
sary
48EZ --A