Carrier 48LJD - Manual (Page 28)

Table 20 — Cooling Service Analysis
PROBLEM 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 Low 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 over­
load open Determine cause. Replace compressor
Defective run/start capacitor, overload, start relay. Determine cause and replace.
One leg of three-phase power dead. Replace fuse or reset circuit breaker. Determine cause.
Compressor cycles
(other than normally
satisfying
thermostat).
Refrigerant overcharge or undercharge. Reclaim 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 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. Reclaim 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. Reclaim excess refrigerant.
Air in system. Reclaim 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 head load. Check for source and eliminate
Compressor valves leaking Replace compressor.
Refrigerant overcharged. Reclaim 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 and replace If
necessary.
Temperature too low in conditioned area Reset thermostat.
Outdoor ambient below 25 F. Install low-ambient kit
Evaporator fan will
not shut off. Time off delay not finished Wait for 30-second off delay.
28