Troubleshooting - Carrier 50ZH024-060 Installation, Start-Up And Service Instructions Manual

SYMPTOM
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.
Excessive head pressure.
Head pressure too low.
Excessive suction pressure.
Suction pressure too low.
Compressor runs but
outdoor fan does not.
Table 8—Troubleshooting—Cooling and Heating
CAUSE
Power Failure
Loss of Charge
Switch open
Fuse blown or circuit breaker tripped
Defective thermostat, contractor, 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 3-phase power dead
Low input voltage
(20 percent low)
Refrigerant overcharge or undercharge
Loss of Charge
Switch open
Defective compressor
Insufficient line voltage
Blocked outdoor coil (cooling)
Defective run/start capacitor, overload or start
relay
Defective thermostat
Faulty outdoor-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
Frosted outdoor coil with incorrect
defrost operation (heating)
Air in refrigerant system
outdoor coil dirty or restricted
Dirty air filter
Dirty outdoor coil
Refrigerant overcharged
Air in refrigerant system
Outdoor or indoor air restricted
or air is recirculating
Low refrigerant charge
Compressor valves leaking
Restriction in liquid tube
High heat load
Compressor valves leaking
Refrigerant overcharged
Dirty air filter (cooling)
Low refrigerant charge
Metering device or low side restricted
Insufficient indoor airflow (cooling)
Temperature too low in conditioned area (cooling)
Outdoor ambient below 40°F (cooling)
Field-installed filter-drier restricted
Normally closed contacts on
defrost board open
Evaluate unit for possible refrigerant leak
Check wiring diagram and rewire correctly
Lower thermostat setting below room tempera-
Recover refrigerant, evacuate system, and re-
charge to capacities shown on nameplate
Evaluate unit for possible refrigerant leak
Check defrost time settings. Reset as necessary.
Check defrost temperature switch. Replace as necessary.
Recover refrigerant, evacuate system, and re-
Recover refrigerant, evacuate system, and re-
22
REMEDY
Call power company
Replace fuse or reset circuit breaker
Replace component
Determine cause and correct
ture
Check wiring and repair or replace
Determine cause
Replace compressor
Determine cause and replace
Replace fuse or reset circuit breaker
Determine cause
Determine cause and correct
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
charge
Clean coil or remove restriction
Replace filter
Clean coil
Recover excess refrigerant
charge
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- replace if necessary
Reset thermostat
Install low-ambient kit
Replace
Check condition of relay on board.
Replace board if necessary.