Carrier 48KHA - Manual (Page 23)

TROUBLESHOOTING CHART
Table 10 — Cooling Service Analysis Chart
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SYMPTOM PROBABLE CAUSE REMEDY
Compressor and con-
denser 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 cycles (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 condi­
tioned area Reset thermostat.
Outdoor ambient below 55 F Install accessory low-ambient kit.
Field-installed filter drier
restricted Replace.
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