Table 27 — cooling service analysis – Carrier 48TJ016-028 User Manual
Page 49
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Table 27 — Cooling Service Analysis
PROBLEM
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.
Three phase power incorrectly connected (sizes Of 6 and
020 only). Indicated by flashing red LED on Phase Moni
tor Relay (PMR) board (see Control Box Component
Arrangement for location).
Correct field power phasing.
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 over
load open.
Determine cause. Replace compressor.
Defective overload.
Determine cause and replace.
Compressor locked out
Determine cause for safety trip and reset lockout.
One leg of 3-phase power dead.
Replace fuse or reset circuit breaker.
Determine cause.
Compressor Cycles
(other than normally
satisfying thermostat).
Refrigerant overcharge or undercharge.
Recover refrigerant, evacuate system, and recharge
to nameplate.
Defective compressor.
Replace and determine cause.
Insufficient line voltage.
Determine cause and correct.
Blocked condenser.
Determine cause and correct.
Defective overload.
Determine cause and replace.
Defective thermostat.
Replace thermostat.
Faulty condenser-fan motor.
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.
Air in system.
Recover 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.
Recover excess refrigerant.
Faulty TXV.
1. Check TXV bulb mounting and secure tightly to
suction line.
2. Replace TXV if stuck open or closed.
Air in system.
Recover 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.
Restriction in liquid tube.
Remove restriction.
Excessive Suction
Pressure.
High heat load.
Check for source and eliminate.
Faulty TXV.
1. Check TXV bulb mounting and secure tightly to
suction line.
2. Replace TXV if stuck open or closed.
Refrigerant overcharged.
Recover 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.
Faulty TXV.
1. Check TXV bulb mounting and secure tightly to
suction line.
2. Replace TXV if stuck open or dosed.
Insufficient evaporator airflow.
increase air quantity. Check filter and replace if
necessary.
Temperature too low in conditioned area.
Reset thermostat.
Field-installed filter drier restricted.
Replace.
LEGEND
TXV
— Thermostatic Expansion Vaive
49