Fridge-Freezer Compressors: What Can Go Wrong

Gemini said

SAFETY DISCLAIMER: Compressor repairs involve high-voltage electricity and pressurized refrigerant. Always unplug the unit before inspection. Never attempt to open the sealed refrigerant system unless you are a licensed professional.

The compressor is the heart of your refrigerator's cooling system. When it fails, the entire appliance stops working. However, many "compressor failures" are actually external electrical issues that are much cheaper to fix.

Key Diagnostic Tips:

• Mechanical Seizure: If the compressor is humming loudly and feels extremely hot to the touch, the internal piston may be stuck.

• Electrical Burnout: If the compressor is completely silent and cold, the internal motor windings may have "opened" or shorted out.

• Valve Failure: If the compressor runs continuously but the fridge stays warm, the internal valves may be worn out, preventing it from pumping refrigerant effectively.

Improved Repair Strategy:

1. The "Shake" Test: Remove the start relay from the side of the compressor. If it rattles, the internal ceramic disk has shattered. Replacing this $20 part often "fixes" a dead compressor.

2. Ohms Testing: Use a multimeter to measure the three pins on the compressor. The resistance between the "Start" and "Common" pins plus "Run" and "Common" should equal the resistance between "Start" and "Run."

3. Check for Grounding: Test each pin against the metal casing of the compressor. If your multimeter shows continuity, the compressor has an internal short and must be replaced.

4. Voltage Supply: Ensure the main control board is actually sending power to the compressor. If there is no voltage at the wires, the board—not the compressor—is at fault.

So what can go wrong with compressors , well they can a do fail they can fail electrically and mechanically but sometimes the control side of things can fail so ensure you are 100% correct when condemning and replacing a compressor as they are expensive and difficult to replace.

The pistons in these compressor sit in a bath of oil that what makes them so reliable obviously a loss of oil would cause failure quite rapidly even seizure of the entire compressor. A seized compressor can still be attempting to start and this can be heard as a clicking this is the relay and overload protection attempting to start the compressor then cutting out when it cannot and it shuts power off.

Over time seals can wear and reduce the pumps efficiency sometimes you can tap on a compressor and it will alter the pressure reading this is a symptom of bad seals. 

Windings can fail open or shorted so measuring these correctly depending on the type of compressor is very important. When testing a normal compressor the 2 start run winding reading should equal the final measurement.  when testing invertor winding they all should be equal and the LG linear invertor compressor only has one measurable winding between 4-9 ohms.