Refrigerator Compressor Hums [Solutions]

Typically, a refrigerator compressor hums quietly. The problem is when the compressor hums loudly or makes strange noises. Find a solution in this article.

Refrigerator Compressor Hums

What Does It Mean When a Refrigerator Compressor Hums?

When the compressor of a refrigerator hums, it means it is in good working condition. A compressor should make a low humming or buzzing sound. From time to time, the sound will stop as the compressor turns off. It is part of the normal operation of a refrigerator.

In refrigerators that have an automatic defrost system, the compressor turns off when the defrost cycle begins. Due to the fact that the compressor is the center of the cooling system, it cannot run alongside the defrost cycle.

However, if the compressor makes a loud humming sound, begins to rattle and vibrate, clicks on and off, or makes a high-pitched sound, test the compressor. You may be unable to test it yourself, so hire a professional to run the test and recommend a permanent solution.

Refrigerator Compressor Humming But Not Cooling – Quick Fix

If you find your refrigerator making a low humming sound but the refrigerator is not cooling or the compressor is running hot, check the following:

  • Thermostat setting
  • Condenser fan
  • Condenser coils
  • Evaporator coils
  • Refrigerant
  • Evaporator fan
  • Compressor

One or more of these components is causing the compressor to seem as if it is working normally when it is not. Sometimes, the problem stems from the compressor itself, as this article explains.

Refrigerator Compressor Hums and Clicks Off – How to Fix

Before checking any component, determine how long the compressor runs before it clicks off. A refrigerator compressor does not constantly run. It hums lowly and turns off several times a day for the defrost cycle to run. After about 30 minutes, the compressor turns on again to cool the refrigerator. So, if this process is what you notice with your refrigerator, it is normal.

But, if the compressor hums and clicks off within seconds, check the start relay or overload protector. The start relay is the tiny black device mounted on one side of the compressor. It is pretty easy to check it for faults.

Unmount it and give it a shake. A rattle from the relay lets you know it is faulty and needs a replacement. Burnt marks or smell from the relay further cements this fact.

However, if the relay does not rattle or have a burnt smell, check its continuity between the start and run terminals using a multimeter. If you get no continuity between the terminals, replace the start relay.

The device enables the compressor to start and run smoothly. Without the start relay, the compressor will not start. Even if you manage to start the compressor, it can only run temporarily. And if the relay is faulty, the compressor will start and click off within seconds.

1. Dirty Condenser Coils

The condenser coils should be cleaned once or twice every year. If the coils are dirty, the compressor will get an overload of heat and shut down to protect itself. You may hear it hum briefly and click off. Cleaning the coils will solve the problem if the compressor is too hot.

The condenser coils are a part of the cooling process. They condense the refrigerant, and during the process, the gas generates heat. It is the duty of the coils to release the heat into the air outside the refrigerator so it does not overheat. But dirt keeps them from working optimally. Therefore, it is crucial to keep them free of dust and other debris.

As equally important is creating enough space around the refrigerator, especially at the back. It would be an exercise in futility if the coils release the heat, but it remains trapped at the refrigerator’s back. So, leave about two inches between the unit and the wall behind it.

2. Condenser Fan

The fan also helps in the cooling process. While the coils dissipate heat, the fan ensures they don’t get too hot. It also keeps the compressor from overheating. So, if you find the compressor humming and clicking off, the fan may be faulty.

First, ensure the blades are not obstructed and are clean. Then, turn them to check their functionality. If the blades don’t spin well, it may indicate a problem with the motor, probably worn bearings. But if the blades spin well, yet the fan fails to run, run a continuity test on the motor using a multimeter. Replace the fan’s motor if you get no continuity.

3. Power Overload

Sometimes, the compressor draws more voltage or power than it needs at a time. The overload causes it to shut itself down as a form of protection. But you may hear it clicking on and off afterward. Unplug the refrigerator from the wall outlet, wait about five minutes, and plug it back into the outlet.

The compressor should start and run without clicking off within a short period. If the problem continues, it may indicate that the compressor is failing. Get a service technician to look at the compressor and recommend a permanent fix.

Check out these other articles…

Refrigerator Compressor Leaking [How to Fix]

Refrigerator Compressor Failure [How to Fix]

Refrigerator Not Cooling [Proven Solutions]

Refrigerator Compressor Overload [Solutions]

Refrigerator Compressor Turning On and Off [Issues Solved]

Refrigerator Compressor Is Rattling [How to Fix]

Refrigerator Compressor Locked Up [How to Fix]

Refrigerator Compressor Just Hums

The sound you hear when a refrigerator is running, like a low buzz or hum, is the compressor. A refrigerator compressor should quietly hum if everything is in good working condition. So, if the refrigerator is cooling correctly, the quiet hum is normal.

Check the refrigerator to see whether or not it is cooling while the compressor hums. If the refrigerator is cooling, and the hum from the compressor is not loud, all is well. But if the refrigerator is not cooling, there is a problem, whether or not the compressor hums quietly. The upside here is that the problem may not stem from the compressor.

Troubleshoot the condenser coils, evaporator coils, evaporator fan, condenser fan, thermostat, thermistor, and start relay. When you find these components in good working condition, check the main control board.

What Causes a Refrigerator to Hum Loudly?

Dirty condenser coils cause a refrigerator to hum loudly. Typically, they work to release heat from the refrigerator but do so quietly. However, if they get significantly dirty, they cannot remove the heat efficiently and quietly. So, you hear a loud noise coming from the area. Cleaning the coils usually solves the loud humming noise.


A refrigerator compressor should make a low humming noise if all is working well. The problem is when the refrigerator compressor hums loudly. If all the steps above don’t help fix this issue in your refrigerator, contact the manufacturer.

As an alternative, use the chatbox to your right to reach us. We will connect you to an appliance technician for immediate assistance.

If you are going to repair the refrigerator yourself, remember to disconnect it from electric power. It is one of the first steps in keeping you safe from accidental electrocution.

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