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14
Table 1 — Cooling Service Analysis
PROBLEM 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 three-phase power is dead.
Replace fuse or reset circuit breaker. Determine
cause.
Compressor Cycles (other than normally
satisfying thermostat).
Refrigerant overcharge or undercharge.
Recover refrigerant, evacuate system, and
recharge to 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 and replace if
necessary.
Temperature too low in conditioned area.
Reset thermostat.
Outdoor ambient below 25°F.
Install low-ambient kit.
Evaporator Fan Will Not Shut Off.
Time off delay not finished.
Wait for 30 second off delay.
Compressor Makes Excessive Noise.
Compressor rotating in wrong direction.
Reverse the 3-phase power leads.
Summary of Contents for 50LC 14
Page 26: ...26 Fig 34 50LC 14 26 Control Wiring Diagram...
Page 27: ...27 Fig 35 50LC 14 26 RTU Open Control Wiring Diagram...
Page 28: ...28 Fig 36 50LC 14 20 208 230V 3 Phase Power Wiring Diagram...
Page 29: ...29 Fig 37 50LC 24 26 208 230V 3 Phase Power Wiring Diagram...
Page 30: ...30 Fig 38 50LC 14 26 460V 575V 3 Phase Power Wiring Diagram...