Lawn Equipment Parts
How To Repair A Freezer That's Not Working
Start Relay or Controller
If your freezer won’t start, one of the most common parts to fail is the compressor start relay. Sometimes called the controller, this device is used to energize the compressor start windings until the unit is running, and it usually contains the overload protection component as well. If the relay or controller is defective, the compressor won’t start. The controller is located on the side of the compressor and can be checked for continuity with a multi-meter. Look for any signs of overheating or arcing on the device and replace with only the manufacturer’s suggested part. Remember to remove the power before attempting any repair.
Electronic Control Board
If your electronic display model freezer won’t start, then you may have a problem with the control board. On some models this electronic control is used to display, monitor, and adjust the internal temperature of the freezer, as well as to control the operation of the compressor, evaporator fan motor and defrost heater circuits. On some models there may also be a separate control board located at the rear that controls these circuits. If either electronic control has failed, the compressor may not start. Inspect the control board for any signs of arcing or corrosion and replace if any are found. Further testing will require the use of a multi-meter to check for voltage in a live circuit and should only be performed by trained technicians.
Temperature Control or Thermostat
If your freezer won’t start, then you may have a problem with the temperature control thermostat. The rotary dial thermostat or temperature control uses a capillary tube sensor that attaches to the inside liner of the freezer to monitor the temperature, and also has a set of internal electrical contacts that supply power to the compressor circuit. When the temperature at the sensor rises, a pressure change occurs at the control and the switch contacts will close and turn on the compressor. If the contacts become corroded, or if the sensor bulb is damaged, the compressor may not start and the control will need to be replaced. You can also check the control for continuity using a multi-meter. Be sure to unplug the freezer before attempting any repair.
If your freezer won’t start, you may have a defective start capacitor. This device is used to help energize the compressor start windings until the unit is running. If the capacitor is defective, the compressor might hum but may not start. The capacitor is located on the side of the compressor and is usually attached to the start relay and overload device or controller. Look for any signs of overheating or arcing on the capacitor and replace with only the manufacturer’s suggested part. Further testing of the capacitor requires a specific type of meter and should only be performed by a trained technician. Remember to remove the power before attempting any repair.
If your freezer won’t start and is a frost free model, then you may have a problem with the defrost timer. These models perform a periodic defrost cycle to melt any frost that accumulates on the evaporator coil, and the timer is part of this circuit. The defrost timer has internal contacts that alternately supply power to the defrost heater circuit and to the compressor circuit. If the timer stalls in the defrost mode or if the contacts corrode, the compressor will not start. The timer is normally located at the rear of the freezer and should have a slotted shaft to allow you to manually advance the timer. If you manually advance the defrost timer and the compressor starts then the timer will need to be replaced. If the compressor doesn’t start you should also check to see if you have power coming from the timer contacts. This will require a live voltage test and should only be performed by a trained technician or someone who is comfortable working with live electrical circuits.