Table 5—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, con-
trol relay, high pressure, or loss-of-charge swtich
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 tempera-
ture
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 (50GL030-060)
makes excessive noise, and there may be a
low pressure differential
Scroll compressor is rotating in the wrong direc-
tion
Correct the direction of rotation by reversing two
of the 3-phase power leads to the unit. Shut
down unit to allow pressures to equalize
Compressor cycles (other than normally sat-
isfying thermostat)
Refrigerant overcharge or undercharge
Recover refrigerant, evacuate system, and re-
charge 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 re-
charge
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 re-
charge
Condenser 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 liquid tube
Remove restriction
Excessive suction pressure
High heat load
Check for source and eliminate
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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