Most upright freezer problems are easy to diagnose and repair. You can make many repairs yourself, but if the repair involves working with refrigerants, you must have a licensed technician complete the repair. Only a technician certified by the Environmental Protection Agency to work with refrigerants can legally make those repairs.
Freezer Does Not Run
When troubleshooting any appliance that does not start, always look for obvious causes -- unplugged power cord, a blown fuse or a tripped circuit breaker -- before checking the internal wiring and components. Many things can keep a freezer from starting: a bad cold control or thermostat control, a bad start relay, a bad defrost timer or a bad compressor. If the compressor hums, but does not run, the problem might be a bad start relay or compressor. Modern refrigerators and freezers use a solid state start relay, and the best way to test one is to substitute a known good relay. Compressors have two electrical coils, a start winding and a run winding. If either becomes an open circuit, the compressor will not run. A seized-up rotor shaft will also keep the freezer from running. If the compressor is at fault, call a technician to replace it. A cold control stuck in the open position or a defrost timer stuck in the defrost position will also keep the freezer from running.
Freezers come with diagrams affixed to the back of the appliance or to the inside of their compressor compartments. The schematic diagram shows the electrical connections between the components. The pictorial diagram shows the physical location of the components within the freezer cabinet.
Does Not Get Cold Enough
This problem could be caused by a bad cold control or a problem with the refrigerant system. The cold control is nothing more than a thermostat that controls current flow to the compressor, just as the thermostat controls your home heating system. The thermostat’s bimetallic springs can weaken and allow the contacts to open early; shutting down the compressor before the set temperature is reached. Bypass the cold control and see whether the freezer gets cold. If that does not work, call a technician to check refrigerant levels and pressures.
Excessive Ice Buildup
Ice buildup in the freezer cabinet is an indication that the auto defrost system is not working. In most cases the problem is a defective defrost timer. Manually turn the defrost timer clockwise until the compressor shuts down and then wait to see whether the ice melts. If the ice remains, you have a bad defrost heater or a bad defrost thermostat and will need to replace that component.