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TROUBLESHOOTING COOLING CHART
SYMPTOM CAUSE REMEDY
Compressor and con-
denser 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.
Single-phase units with scroll compressor
(50SS048,060 and 50SX) have a 5-minute time delay
DO NOT bypass this compressor time delay — wait
for 5 minutes until time-delay relay is deenergized.
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,
or 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
(50SS048, 060;
50SX036-060
units only) makes ex-
cessive noise, and
there may be a low
pressure differential.
Scroll compressor is rotating in the
wrong direction
Correct the direction of rotation by reversing the
3-phase power leads to the unit.
Compressor cycles
(other than normally
satisfying thermostat).
Refrigerant overcharge or undercharge Reclaim 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 Reclaim 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 Reclaim excess refrigerant.
Air in system Reclaim 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 Reclaim 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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