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TROUBLESHOOTING
Cooling
SYMPTOM CAUSE REMEDY
Compressor and
condenser fan will
not start.
Power failure Call power company.
Fuse blown or circuit breaker tripped Replace fuse or reset circuit breaker.
Defective thermostat, contactor, transformer,
or control relay
Replace component.
Insufficient line voltage Determine cause and correct.
Incorrect or faulty wiring Check wiring diagram and rewire correctly.
Thermostat setting too high Lower thermostat setting below room temperature.
Compressor will not
start but condenser
fan runs.
Faulty wiring or loose connections in
compressor circuit
Check wiring and repair or replace.
Compressor motor burned out, seized, or
internal overload open
Determine cause. Replace compressor.
Defective run/start capacitor, overload,
start relay
Determine cause and replace.
One leg of 3-phase power dead Replace fuse or reset circuit breaker.
Determine cause.
Three-phase scroll
compressor (Units
48SS048,060 and
48SX036-060 only)
makes excessive
noise, and there
may be a low pres-
sure differential.
Scroll compressor is rotating in the
wrong direction
Correct the direction of rotation by reversing the
3-phase power leads to the unit. Shut down unit to
allow pressures to equalize.
Compressor cycles
(other than normally
satisfying
thermostat).
Refrigerant overcharge or undercharge Recover refrigerant, evacuate system, and
recharge to capacities shown on nameplate.
Defective compressor Replace and determine cause.
Insufficient line voltage Determine cause and correct.
Blocked condenser Determine cause and correct.
Defective run/start capacitor, overload
or start relay
Determine cause and replace.
Defective thermostat Replace thermostat.
Faulty condenser-fan motor or capacitor Replace.
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.
Thermostat set too low Reset thermostat.
Low refrigerant charge Locate leak, repair, and recharge.
Leaking valves in compressor Replace compressor.
Air in system Recover refrigerant, evacuate system, and recharge.
Condenser coil dirty or restricted Clean coil or remove restriction.
Excessive head
pressure.
Dirty air filter Replace filter.
Dirty condenser coil Clean coil.
Refrigerant overcharged Recover excess refrigerant.
Air in system Recover refrigerant, evacuate system, and recharge.
Condenser air restricted or air short-cycling Determine cause and correct.
Head pressure too
low.
Low refrigerant charge Check for leaks, repair and recharge.
Compressor valves leaking Replace compressor.
Restriction in liquid tube Remove restriction.
Excessive suction
pressure.
High heat load Check for source and eliminate.
Compressor valves leaking Replace compressor.
Refrigerant overcharged Recover excess refrigerant.
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 evaporator airflow Increase air quantity. Check filter — replace if
necessary.
Temperature too low in conditioned area Reset thermostat.
Outdoor ambient below 40 F Install low-ambient kit.
Field-installed filter-drier restricted Replace.
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