Troubleshooting The Cooling System - Carrier WeatherMaker 50TC 17-30 Series Service And Maintenance Instructions

TROUBLESHOOTING THE COOLING SYSTEM

Refer to Table 5 for additional troubleshooting topics.
PROBLEM
Compressor and Condenser Fan
Will Not Start
Compressor Will Not Start But
Condenser Fan Runs
Compressor Cycles (other than
normally satisfying thermostat)
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 5 — Cooling Service Troubleshooting
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 compressor
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. Determine cause and replace.
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.
Faulty TXV valve.
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.
Faulty TXV valve.
Insufficient evaporator airflow.
Temperature too low in conditioned area.
Outdoor ambient below 25°F.
Time off delay not finished.
Compressor rotating in wrong direction.
Call power company.
Replace fuse or reset circuit breaker.
Replace defective component.
Determine cause and correct.
Check wiring diagram and rewire correctly.
Lower thermostat setting below room temperature.
Check wiring and repair or replace. Tighten loose
connections.
Determine cause. Replace compressor.
Determine cause and replace defective component.
Replace fuse or reset circuit breaker. Determine
cause.
Recover refrigerant, evacuate system, and recharge
to values on nameplate.
Replace defective compressor.
Determine cause and correct.
Determine cause and correct.
Replace thermostat.
Replace. Defective fan motor or capacitor.
Locate restriction and remove.
Replace filter.
Decrease load or replace with larger unit.
Reset thermostat.
Locate leak; repair and recharge.
Replace compressor.
Recover refrigerant, evacuate system, and recharge.
Clean coil or remove restriction.
Replace air filter.
Clean condenser coil.
Recover excess refrigerant.
1. Check TXV bulb mounting and secure tightly to
suction line and insulate.
2. Replace TXV valve and filter drier if stuck open or
closed.
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.
1. Check TXV bulb mounting and secure tightly to
suction line and insulate.
2. Replace TXV valve and filter drier if stuck open or
closed.
Increase air quantity. Check filter and replace if
necessary. Check belt tension on blower.
Reset thermostat.
Install low-ambient kit.
Wait for 30 second off delay.
Reverse the 3 phase power leads.
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REMEDY