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Table 11 – Troubleshooting Guide -- Cooling or Heat Pump Heating Mode
SYMPTOM CAUSE REMEDY
Compressor and Outdoorfanwillnot
start.
Power Failure Call power company.
Fuse blown or circuit breaker tripped Replacefuseorresetcircuitbreaker.
Defective thermostat, contactor, transformer, or control
relay
Replace component.
Insufficient lin e voltage Determine cause andcorrect.
Incorrector faulty wiring Check wiring diagram and rewire correctly.
Thermostat setting too high Lower thermostat setting below room temperature.
Compressor willnot start butOutdoor
fan runs.
Faulty wiring orloose connections in compressor circuit Check wiring and repair or replace.
Compressor motor burnedout, seized, or internal over-
loadopen
Determine cause Replace compressor .
Defective run/startcapacitor, overload, start relay Determine cause and replace.
Onelegof3---phasepowerdead
Replace fuse or resetcircuitbreaker. Determine
cause.
Three---phase scroll compressor makes
excessive noise,and there may
be a low pressure diffe rential.
Scroll compressoris rotating in the wrong direction
Correct the direction of rotation by reversing the
3---phasepower leads to theunit.
Compressor cycles (other than normally
satisfying thermostat).
Refrigerant overchargeor undercharge
Recover refrigerant, evacuate system,and recharge
to capacities shown on nameplate.
Defective compressor Replace and determine cause.
Insufficient lin e voltage Determine cause andcorrect.
Blocked Outdoor Determine cause andcorrect.
Defective run/startcapacitor,overload or start relay Determine cause andr eplace.
Defective thermostat Replace thermostat.
Fa ulty Ou tdoor---fan motor or capacitor Replace.
Damaged reversing valve Determine cause andcorrect
Restriction in refrigerant system Locate restriction and remove.
Compressor operates continuously.
Dirty air filter Replace filter.
Unitundersized for load Decrease load or increase unit size.
Thermostat set too low Res et thermostat.
Low refrigerant charge Locate leak,r epair,and recharge.
Mechanical damage in compressor. Replace compressor.
Air in system Recover refrigerant, evacuate system, andrecharge.
Frosted coil with incorrect defrostoperation
Check defrost time settings, Reset as necessary
Check def r ost temperatur e switch, Repl ace as nec-
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.
Refrigerantovercharged Recover excess refrigerant.
Air in system Recover refrigerant, evacuate system, andrecharge.
Indoor or Outdoor air restricted or air short---cycling Determine cause andcorrect.
Head pressure too low.
Low refrigerant charge Check for leaks, repair,and recharge.
Compressor IPR leaking Replace compressor.
Restrictioninliquidtube Remove restriction.
Excessive suctio n pressure.
High heat load Checkfor source and eliminate.
Compressor IPR leaking Replace compressor.
Refrigerantovercharged Recover excess refrigerant.
Reversing valve hungup or leaking internally Repl ace valve
Suction pressure too low.
Dirty air filter Replace Filter.
Low refrigerant charge Check for leaks, repair,and recharge.
Metering device or low side restricted Remove source of restriction.
Insufficient Indoor airflow
Increase air qu an tity. Checkfilter — replace if neces-
sary .
Temper atur e too low in conditioned area Reset thermostat.
Outdoor ambient bel ow 55°F (12.8°C) In stall 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) contactson defrost board open
Check condition of relay on board Repl ace if neces-
sary
48VT--A