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PROBLEM
Compressor and Outdoor Fan Will
Not Start.
Compressor Will Not Start But
Outdoor Fan Runs.
Compressor Cycles (Other Than
Normally Satisfying Thermostat).
Compressor Operates
Continuously.
Compressor Makes Excessive
Noise.
Excessive Head Pressure.
Head Pressure Too Low.
Excessive Suction Pressure.
Suction Pressure Too Low.
CHS-180-240-01SI Rev. A
TROUBLESHOOTING
CAUSE
Power failure.
Fuse blown or circuit breaker tripped.
Defective thermostat, contactor, transformer, control
relay, or capacitor.
Insufficient line voltage.
Incorrect or faulty wiring.
Thermostat setting too high.
High pressure switch tripped.
Low pressure switch tripped.
Freeze-up protection thermostat tripped.
Fan fault or shutdown condition in fan coil unit active,
preventing thermostat signals passing from fan coil
unit to CHS.
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 3-phase power dead.
Refrigerant overcharge or undercharge.
Defective compressor.
Insufficient line voltage.
Blocked outdoor coil or dirty air filter.
Defective run/start capacitor, overload, or start relay.
Defective thermostat.
Faulty outdoor-fan (cooling) or indoor-fan (heating)
motor or capacitor.
Restriction in refrigerant system.
Dirty air filter.
Unit undersized for load.
Thermostat set too low (cooling).
Low refrigerant charge.
Air in system.
Outdoor coil dirty or restricted.
Compressor rotating in the wrong direction.
Dirty outside air or return air filter (heating).
Dirty outdoor coil (cooling).
Refrigerant overcharged.
Air in system.
Condensing air restricted or air short-cycling.
Low refrigerant charge.
Compressor scroll plates defective.
Restriction in liquid tube.
High heat load.
Compressor scroll plates defective.
Refrigerant overcharged.
Dirty air filter (cooling).
Dirty or heavily iced outdoor coil (heating).
Low refrigerant charge.
Metering device or low side restricted.
Insufficient indoor airflow (cooling mode).
Temperature too low in conditioned area.
Field-installed filter drier restricted.
Outdoor ambient below 25°F (cooling).
Outdoor fan motor(s) not operating (heating).
Specifications subject to change without notice.
REMEDY
Call power company.
Replace fuse or reset circuit breaker. Determine root
cause.
Replace component.
Determine cause and correct.
Check wiring diagram and rewire correctly.
Lower thermostat setting below room temperature.
See problem "Excessive head pressure."
Check system for leaks. Repair as necessary.
See problem "Suction pressure too low."
Reset address fault in VFD (FHX).
Check wiring and repair or replace.
Determine cause. Replace compressor or allow
enough time for internal overload to cool and reset.
Determine cause and replace compressor.
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.
Recover refrigerant, evacuate system, and recharge.
Clean coil or remove restriction.
Reverse the 3-phase power leads as described in
Start-Up.
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.
Clean outdoor coil. Check defrost cycle operation.
Check for leaks; repair and recharge.
Remove source of restriction.
Increase air quantity. Check filter and replace if
necessary.
Reset thermostat.
Replace.
Install low-ambient kit.
Check fan motor operation.
33
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