How to Test a Fridge Compressor: A Step-by-Step Guide
How to Test a Fridge Compressor: A Step-by-Step Guide
Blog Article
The refrigerator is one of the most essential appliances in any home, tirelessly preserving your food and keeping it fresh. At the heart of every refrigerator lies the compressor, a vital component responsible for circulating refrigerant through the system. If your fridge isn’t cooling properly or making unusual noises, the compressor could be the culprit. Fortunately, with a few tools and precautions, you can test a fridge compressor yourself to diagnose potential problems before calling a professional.
In this article, we’ll cover everything you need to know about testing a refrigerator compressor — from understanding how it works to performing safe and effective diagnostic tests.
What Is a Fridge Compressor and How Does It Work?
A compressor in a refrigerator functions much like a pump. It compresses the refrigerant gas and pushes it through the condenser coils located at the back or bottom of the appliance. The refrigerant then releases heat and cools down before moving through the evaporator coils inside the fridge, absorbing heat and reducing the temperature inside the unit.
When the compressor fails or operates inefficiently, the cooling performance of the fridge drops significantly, potentially leading to food spoilage and increased energy consumption. Follow for more information www.aeg-homeuae.com.
Signs of a Faulty Fridge Compressor
Before diving into testing, look out for these common signs of compressor problems:
Fridge isn’t cooling properly
Unusual humming, clicking, or knocking sounds
Compressor overheats
Fridge turns on and off frequently (short cycling)
Tripped circuit breakers
Compressor won’t start at all
If you notice any of these symptoms, it’s a good idea to test the compressor to determine if it’s the source of the issue.
Tools You’ll Need
To safely and accurately test a refrigerator compressor, gather the following tools:
Multimeter (with ohmmeter function)
Screwdriver
Protective gloves
Insulated pliers (optional)
Capacitor tester (optional)
Safety First: Precautions to Take
Before working on your fridge:
Unplug the refrigerator from the wall outlet to eliminate the risk of electric shock.
Allow the compressor to cool down if the fridge has been running.
Use protective gloves and handle components carefully.
Step-by-Step Guide to Testing a Fridge Compressor
1. Locate the Compressor
The compressor is usually found at the back of the fridge, at the bottom behind a panel or grill. It’s a black, dome-shaped component with copper tubes attached to it.
Remove the cover panel using a screwdriver to access the compressor and its electrical terminals.
2. Identify the Compressor Terminals
You’ll find a plastic cover on the side of the compressor, housing the start relay, overload protector, and three metal terminals arranged in a triangle:
Common (C)
Start (S)
Run (R)
Remove the plastic cover carefully to expose these terminals.
3. Test Compressor Windings with a Multimeter
Set your multimeter to the ohms (Ω) setting to check for continuity and resistance between the terminals.
Test Common to Start (C-S)
Test Common to Run (C-R)
Test Start to Run (S-R)
A typical healthy reading for each winding is between 2 and 10 ohms, though exact values can vary by model. Refer to your fridge’s service manual for specific resistance values.
If you get a reading of zero or infinity (open circuit) on any of these tests, the compressor’s internal windings may be damaged.
4. Check for Ground Fault
Now, test for a short to ground:
Place one multimeter probe on the metal casing of the compressor.
Place the other probe on each of the three terminals (C, S, R) one at a time.
There should be no continuity (infinite resistance). If the multimeter shows any continuity (zero or low ohms), the compressor is grounded and should be replaced.
5. Inspect the Start Relay and Overload Protector
If the compressor windings check out, the issue might lie with the start relay or overload protector. These components are attached to the compressor terminals and help initiate the motor operation.
Remove the relay and shake it gently. If it rattles, it’s likely defective.
Test the relay for continuity using your multimeter.
Do the same for the overload protector, which should also have continuity.
Replacing these inexpensive parts is often a quick fix for compressor start issues.
6. Test the Capacitor (If Applicable)
Some refrigerators use a start capacitor to give the compressor an initial jolt of energy. If your fridge has one:
Disconnect the capacitor.
Use a capacitor tester or a multimeter with a capacitance setting to test its value.
Compare the reading to the rated value printed on the capacitor’s casing.
A faulty capacitor can prevent the compressor from starting.
What to Do If the Compressor Fails the Test
If the compressor fails any of these tests — especially showing open windings, continuity to ground, or high resistance — it likely needs to be replaced. Compressor replacement is a complex and costly repair that often requires specialized tools and refrigerant handling, so it’s typically best left to a licensed appliance technician.
In some cases, replacing the start relay, overload protector, or capacitor might resolve compressor startup issues without the need for full replacement.
Conclusion
Testing a refrigerator compressor might seem intimidating, but with the right tools, a little patience, and careful attention to safety, it’s entirely possible for a skilled DIYer to perform an initial diagnosis. By checking the compressor windings, grounding, and associated components like the start relay and capacitor, you can narrow down the source of fridge cooling problems and decide whether a quick repair or professional service is necessary.
Remember: always prioritize safety when dealing with electrical appliances. If you’re unsure about any step in the process, it’s a good idea to consult a qualified appliance technician.