Fridge Compressor Not Starting? Causes and How Technicians Diagnose It

When a fridge will not get cold and you can hear the compressor clicking, or you hear nothing at all, it is easy to assume the compressor has died. Often it has not. A compressor needs power from the control system, help from a start relay or board to get going, and good airflow to keep cool. When any of those fail, the compressor will not start even though it may be perfectly healthy.

Fridge Compressor Not Starting: The Short Answer

If the fridge compressor is not starting, the most common causes are a faulty start relay or overload protector, a failed control board or inverter board, a faulty thermostat or temperature sensor, overheating from a dirty condenser or failed fan, or failed compressor windings. A technician tests these in order, starting with the cheaper parts, before confirming the compressor itself has failed.

Signs the Compressor Is Not Starting

• the fridge is warm but the light and fans work
• a click, a short hum, then silence, repeating every few minutes
• the compressor housing is cold and still
• the compressor is very hot and keeps cutting out
• the safety switch trips when the fridge calls for cooling

Common Causes

Start relay or overload failure

The start relay gives the compressor a boost to get started, and the overload protects it from overheating or drawing too much current. Both are small parts that fail regularly. A faulty relay or overload produces the classic click, hum and click pattern.

Control board or inverter board fault

The control board decides when the compressor should run. Many modern fridges use an inverter board to drive a variable-speed compressor. If the board fails, the compressor receives no power or the wrong signal.

Thermostat or sensor fault

If the thermostat or temperature sensor reports that the fridge is cold when it is not, the compressor is never asked to start. Our guide on resetting a fridge thermostat explains how to check the settings first.

Overheating

Dust-covered condenser coils or a failed condenser fan trap heat. The compressor overheats, the overload cuts it off, and it will not restart until it cools down.

Failed compressor windings

When the windings inside the compressor fail or short to earth, the compressor needs replacing. This is the most serious cause and should only be confirmed after the other parts have been tested.

Compressor clicking but not starting? Call Ace Fridge Repairs on 0452 462 556.

How Technicians Diagnose the Fault

1. Confirm the control system is calling for cooling.
2. Test the start relay and overload.
3. Check the control or inverter board output.
4. Measure the compressor winding resistance and test for a short to earth, with the power isolated.
5. Check condenser and fan condition and running current once the compressor starts.
6. Check refrigerant pressures if needed, under an ARC licence.

This work involves live electrical components and should only be done by a qualified technician. For the safe checks you can do yourself, see our guide on how to test a refrigerator compressor.

What to Do While You Wait

Keep the doors closed, move high-risk food to another fridge or an esky, and switch the fridge off at the wall if it is tripping the power. Cleaning the condenser coils with the power off can help if overheating is the cause.

Compressor Repairs Across Sydney

Ace Fridge Repairs diagnoses compressor faults for homes and businesses across Greater Sydney, including the CBD, Parramatta, Potts Point and Campbelltown, from our base at 93B Pagoda Crescent, Quakers Hill NSW 2763. Repairs carry a 12-month warranty on parts and labour. See the suburbs we service and our guide to signs of a bad compressor.

For residential or commercial fridge repairs, call 0452 462 556, 24/7.

Frequently Asked Questions