How to Troubleshoot the Frost and Defrost on a Kenmore Refrigerator Freezer

How Auto Defrost Works

• A Kenmore refrigerator’s automatic defrost system works similarly to other brands with this feature. A timer toggles the refrigerator between a cooling cycle and a defrost cycle at regular intervals. The refrigerator spends most of its time in the cooling mode. During that time, frost begins to accumulate on the evaporator coil because of the cold temperatures in that area and the presence of condensation on the coil. Often frost will also appear inside the freezer compartment. When the timer indicates it is time to defrost the coil, it breaks a connection to the compressor and turns the defrost heater on. The heater melts the frost, which drains away. After enough time has passed to clear the frost, the timer switches the compressor back on and turns the heater off, and cooling resumes. Automatic defrost heaters are able to melt away all the frost in the freezer and makes it unnecessary perform a manual defrost.

Defrost Heater

• One potential problem that could be causing frost to build up on the evaporator coil or on the surrounding compartment is a faulty defrost heater. The heater, made up of a wire filament inside a quartz, glass or metal casing, is powered on when the timer makes the proper component connections. But if the heater loses its continuity because the filament is burned out then the electricity flowing to the heater will have no effect. If the rest of your defrost system appears to be working normally you should use an ohmmeter to test the continuity of the heating element or have a service professional do it for you. If it is faulty a simple replacement should take care of the situation.

Defrost Timer

• A common reason that a Kenmore refrigerator’s defrost system stops working is a faulty defrost timer. The defrost timer is the key component of the entire system. It tells the compressor when to cool or stop cooling, and tells the heater when to begin heating or to shut off. Sometimes a defrost timer can get stuck in either the defrost cycle or the cooling cycle. When this happens, you’ll need to replace the timer. A professional can take care of this simple, inexpensive repair in just a few minutes. A timer stuck in cooling mode result in excessive frost build-up and eventually interferes with airflow throughout the refrigerator. A timer stuck in defrost means the entire refrigerator stops cooling and warms up to unsafe temperatures.

Freezer Burn

• If the food stored in your freezer routinely suffers from freezer burn, it could be because of the defrost system. It is a rare problem, but when the defrost system malfunctions and causes both the cooling system and the defrost heater to be energized at the same time, it causes constant thawing and refreezing of foods. This leads to freezer burn and ruins the flavor of your food. Call a service technician to deal with this problem if it persists.