Carrier 48KHA - Manual (Page 21)

TROUBLESHOOTING CHART
Table 10—Cooling Sen/ice Analysis Chart
SYMPTOM PROBABLE 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 3-phase power dead Determine cause. Replace fuse or reset circuit breaker.
Compressor cycle (other than
normally satisfying thermostat) Refrigerant overcharge or undercharge Blow refrigerant, evacuate system, and recharge to nameplate.
Defective compressor Determine cause, replace.
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 Blow 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 Purge excess refrigerant.
Air in system Blow 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 Purge 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—replace if necessary.
Temperature too low in conditioned area Reset thermostat.
Outdoor ambient below 55 F Install accessory low-ambient kit.
Field-installed filter drier restricted Replace.
?1