Carrier 48KLA - TROUBLESHOOTING COOLING ISSUES; Cooling Service Analysis Chart

TROUBLESHOOTING CHART
Table 10 — Cooling Service Analysis Chart
SYMPTOM
PROBABLE CAUSE
REMEDY
Compressor and con-
Power failure
Call power company.
denser fan will not start
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
Refrigerant overcharge or
undercharge
Blow refrigerant, evacuate system, and recharge to
nameplate
thermostat)
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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