Carrier 48LC Series Service And Maintenance Instructions page 13

PROBLEM
Compressor and Condenser
Fan Will Not Start.
Compressor Will Not Start But
Condenser Fan Runs.
Compressor Cycles (other
than normally satisfying ther-
mostat).
Compressor Operates
Continuously.
Excessive Head Pressure.
Head Pressure Too Low.
Excessive Suction Pressure.
Suction Pressure Too Low.
Evaporator Fan Will Not Shut
Off.
Compressor Makes Excessive
Noise.
Table 1 – Cooling Service Analysis
CAUSE
Power failure.
Fuse blown or circuit breaker tripped.
Defective thermostat, contactor, transformer,
or control relay.
Insufficient line voltage.
Incorrect or faulty wiring.
Thermostat setting too high.
Faulty wiring or loose connections in compres-
sor circuit.
Compressor motor burned out, seized, or
internal overload open.
Defective run/start capacitor, overload, start
relay.
One leg of three--- phase power dead.
Refrigerant overcharge or undercharge.
Defective compressor.
Insufficient line voltage.
Blocked condenser.
Defective run/start capacitor, overload, or start
relay.
Defective thermostat.
Faulty condenser--- fan motor or capacitor.
Restriction in refrigerant system.
Dirty air filter.
Unit undersized for load.
Thermostat set too low.
Low refrigerant charge.
Leaking valves in compressor.
Air in system.
Condenser coil dirty or restricted.
Dirty air filter.
Dirty condenser coil.
Refrigerant overcharged.
Air in system.
Condenser air restricted or air short--- cycling.
Low refrigerant charge.
Compressor valves leaking.
Restriction in liquid tube.
High head load.
Compressor valves leaking.
Refrigerant overcharged.
Dirty air filter.
Low refrigerant charge.
Metering device or low side restricted.
Insufficient evaporator airflow.
Temperature too low in conditioned area.
Outdoor ambient below 25° F.
Time off delay not finished.
Compressor rotating in wrong direction.
REMEDY
Call power company.
Replace fuse or reset circuit breaker.
Replace component.
Determine cause and correct.
Check wiring diagram and rewire correctly.
Lower thermostat setting below room temperature.
Check wiring and repair or replace.
Determine cause. Replace compressor.
Determine cause and replace.
Replace fuse or reset circuit breaker. Determine
cause.
Recover refrigerant, evacuate system, and recharge
to nameplate.
Replace and determine cause.
Determine cause and correct.
Determine cause and correct.
Determine cause and replace.
Replace thermostat.
Replace.
Locate restriction and remove.
Replace filter.
Decrease load or increase unit size.
Reset thermostat.
Locate leak; repair and recharge.
Replace compressor.
Recover refrigerant, evacuate system, and recharge.
Clean coil or remove restriction.
Replace filter.
Clean coil.
Recover excess refrigerant.
Recover refrigerant, evacuate system, and recharge.
Determine cause and correct.
Check for leaks; repair and recharge.
Replace compressor.
Remove restriction.
Check for source and eliminate.
Replace compressor.
Recover excess refrigerant.
Replace filter.
Check for leaks; repair and recharge.
Remove source of restriction.
Increase air quantity. Check filter and replace if
necessary.
Reset thermostat.
Install low--- ambient kit.
Wait for 30--- second off delay.
Reverse the 3--- phase power leads.
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