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Modern Refrigeration and Air Conditioning
Troubleshooting Chart—Domestic Refrigerator-Freezers
Trouble Common Cause Remedy
Stuck compressor. 1. Broken valve.
2. Insufficient oil.
3. Overheated compressor.
1. Replace the compressor.
2. Add oil. If the unit still will not operate, replace
the compressor.
3. If the compressor is faulty for any reason,
replace the compressor.
Frost or ice on a
finned evaporator.
1. Broken defrost timer.
2. Defective defrost heater.
3. Defective thermostat.
1. Check the timer with a test light and replace
if necessary.
2. Replace the heater.
3. Replace the thermostat.
Ice in the drip catcher. 1. Defective drip catcher heater. 1. Replace the heater.
Freezer runs all the
time—temperature
normal.
1. Ice build-up on the evaporator.
2. Thermostat sensing bulb not in contact
with the evaporator surface.
1. Check door gaskets and replace as needed.
2. Place the sensing bulb in contact with the
evaporator surface.
Freezer runs all the
time—temperature
too cold.
1. Faulty thermostat. 1. Test the thermostat and replace as needed.
Freezer runs all the
time—temperature
too warm.
1. Ice buildup in the cabinet insulation. 1. Stop the unit and disconnect power. Melt the ice
and dry the insulation. Seal any cracks or gaps
in the outer shell and try again.
Rapid ice buildup on
the evaporator
1. Leaky door gasket. 1. Adjust the door hinges. Replace the door gasket
if it is cracked, brittle, or worn.
Door on the freezer
compartment freezes
shut
1. Faulty electric gasket heater.
2. Faulty gasket seal.
1. Use alternate gasket heater, or install a new one.
2. Inspect and check the gasket. If the gasket is
worn, cracked, or hardened, replace it.
Freezer works, and
then warms up.
1. Moisture in the refrigerant. 1. Install a drier in the liquid line.
Gradual reduction in
freezing capacity.
1. Wax buildup in the capillary tube. 1. Clean or replace the capillary tube.
Goodheart-Willcox Publisher
Figure 19-5. Continued.
same basic troubleshooting techniques apply. Examine
the symptoms and eliminate the possible causes using
a systematic, logical approach. The following sections
describe some common problems found in domestic
refrigerators and their possible causes.
19.2.3 Ice on the Evaporator
A large build-up of ice on an evaporator acts as
insulation, preventing heat inside the cabinet from
being transferred to the refrigerant in the evaporator.
When this occurs, the evaporator may not be able to
cool the inside of the refrigerator. Ice buildup on the
evaporator is usually caused by a leaky door seal (gas-
ket). In a frost-free or automatic defrost refrigerator, ice
buildup indicates that the defrost feature is not operat-
ing properly.
Faulty Gasket
If the seal on a refrigerator door is not complete,
external air will enter the conditioned space. This
external air will add moisture to the system and cause
abnormal frosting on the evaporator. The frosting could
also be apparent on the walls of the compartment.
If a gasket forms a poor seal in just one location,
a heat gun can be used to apply moderate heat to that
spot on the gasket. When the bad area of the gasket
is sufficiently heated, it becomes pliable and can be
reformed. Sometimes a small amount of silicone grease
can be applied to the gasket to assist in creating an air-
tight seal. The grease allows the gasket to flex more
easily and prevents binding as the door closes.
Old or brittle gaskets allow heat to enter a refrig-
erator and cool air to leak out. Signs of gaskets in need
of replacement include increased system running time