From all the appliances in your home, the fridge is most likely the noisiest. Working non-stop to preserve your food, it has a compressor that starts when the temperature rises above a threshold and stops when the interior is cool again. The compressor’s role is to circulate the refrigerant throughout the system whilst pushing hot gas out through metal coils and dissipating heat into the air. This is how the fridge stays cool and the freezer frozen. Troubles arise when the compressor starts then stops immediately, generally after a second or two. Why does it happen?
An incorrectly adjusted or faulty thermostat is one of the most common reasons why the fridge compressor starts then stops. Dirty coils or ice build-up are other potential culprits. A broken power cord could be another cause, or the compressor, relays, or capacitors could be broken.
Here’s Why Your Refrigerator Compressor Shuts Off After a Few Seconds
Troubleshooting a refrigerator compressor should start with a systematic diagnosis. Here are the things to check before deciding what to do.
Check the Thermostat
An incorrectly set or faulty thermostat is one of the most frequent causes why the fridge compressor starts and stops constantly.
If the set temperature is too low, the frigid temperatures could cause ice to build up inside the unit or directly on the compressor. Ice could prevent the compressor or motor from working properly; the compressor starts when the temperature rises above the set level, but then it struggles to do its job due to all the ice putting a strain on it.
Removing the ice and setting the correct temperature will generally fix the issue. However, you could burn or break the compressor if you don’t solve the problem promptly.
Likewise, if the set temperature is too high, the compressor might start, but the incorrect temperature setting would cause it to stop straight away. You can correct this by setting the thermostat at a lower temperature.
If the thermostat is set at the right temperature, check it to make sure it works properly. A faulty thermostat could lead to the same problem.
Check the Power Cord and Circuit Voltage
If there is nothing wrong with the thermostat, check the fridge’s power cord. Make sure it is plugged in correctly and that it isn’t damaged. A damaged power cord may not let sufficient voltage pass through, causing the compressor to shut off immediately after it starts.
Also, check that the refrigerator plugs directly into the wall outlet. Extension cords may reduce the voltage, and the compressor won’t have sufficient surge power to keep running.
Lastly, you should also make sure that the circuit voltage matches your appliance’s requirements. Some refrigerators require a higher voltage and need to be hardwired. If you’re experiencing the issue with a new fridge, check its manual to make sure it gets enough power.
Clean the Coils
Dirt and debris build up on the refrigerator coils cause the motor and compressor to run hot, ultimately hampering the compressor’s ability to stay on.
To prevent a fridge malfunction, check the coils at the back of the unit regularly. If they’re covered in dust and debris, unplug the appliance and clean them.
Check the Vents Between Fridge and Freezer
In fridge/freezer units, the fridge and the freezer are two separate compartments, but they communicate through vents. These vents could get clogged with debris, or ice might build up inside them. When this happens, the air doesn’t cool properly, overworking the compressor and causing premature wear and tear.
Cleaning these vents is easy with a thin brush or a wire. Alternatively, unplug the unit and let all ice melt. Clean the fridge and plug it in again to see if the problem persists.
Diagnose a Faulty Compressor
If you’ve done everything above but the compressor still has short cycles, you should diagnose the compressor and troubleshoot it.
Start by checking the refrigerant levels. The compressor uses the refrigerant to cool down the unit’s interior; if there is too much or too little of it, the compressor might short cycle.
Next, pay attention to any additional signs telling you that the compressor has gone bad. A loud humming or buzzing noise indicates a problem with the compressor or the motor.
Another thing to check is the compressor relay. This component provides power to the compressor, and if there is a problem with it, your fridge will not work properly. The only way to diagnose a bad relay is by removing and shaking it. If you hear a rattling noise, replace it with a new relay – the operation is straightforward even for beginners.
How To Replace a Fridge Compressor: 7 Easy Steps
Replacing a fridge compressor is often cheaper than buying a new fridge, but you should only do it yourself if you have some experience. Otherwise, a refrigerant leak could be bad for you and the environment. That said, here’s how to do it.
1. Empty and move the fridge
A fridge’s compressor is located at the back of the unit, generally behind a plate at the bottom. In most cases, you’ll have to move the fridge from its place to access the plate, and even though you don’t have to empty the fridge for the purpose, you may find it easier to haul it around if it is empty.
Unplug the unit and remove its contents. Pull the refrigerator away from the wall and turn it so that you can have direct access to the back.
2. Remove the guard plate
The guard plate is a plate at the bottom of the fridge, right under the coils. It protects the compressor, motor, and wires.
Unfasten the screws holding it in place with a flathead or cross screwdriver, then pull the plate to remove it. Wait for 15-20 minutes until the motor and compressor cool off.
3. Remove the compressor
Locate the compressor at the bottom of the unit and check if it is covered by another plate – most compressors have another layer of protection.
Use a socket wrench to remove this plate if present, then snap a photograph to use as a guide when installing the new compressor. Once you’ve done that, unclip the wires off the compressor and remove them from the unit.
4. Install the new compressor
Place the new compressor in the same position as the old one, then rewire it by following the indications in the picture you snapped. Keep in mind that every wire should go in its original position, or you could burn the new compressor when plugging in the fridge.
5. Add refrigerant
After you’ve installed the new compressor, you must fill it with refrigerant. Each appliance has different instructions for this, so check your product’s manual.
If you don’t have the manual, Google your fridge’s brand and model or check the manufacturer’s website for a digital version. Ultimately, contact the brand’s customer support and ask for a manual copy or instructions on how to add the refrigerant to the compressor.
Adding refrigerant is a delicate procedure because inhaling Freon gas fumes is dangerous – and even life-threatening if you inhale it deeply. Thus, if you’re unsure of how to handle it, you should call in a professional.
6. Connect the valves
Compressors circulate the refrigerant through the coils when it’s running but uses valves to trap in the Freon during the idle mode. Connect these valves to the new compressor and secure them with clips or nuts, based on the type of fridge you have.
7. Test the fridge
Reinstall the compressor plate and the guard plate, then plug in your fridge. Set the temperature and wait for the compressor to start. Check if it works properly or if it’s still short cycling. If it is, you should call in a technician to see what’s wrong.
Faulty Fridge Thermostat Symptoms
We already mentioned that a faulty thermostat could cause the compressor to short cycle, but how to test it? Here are three quick ways.
The Fridge is Not Cold Enough
Did you set a cold temperature, but the air in the fridge feels warm even after a regular compressor cycle? The thermostat hasn’t set the right temperature.
The Fridge is Too Cold
Are the items in your fridge incredibly cold? Look inside the unit, especially on the back wall. If you notice ice, the fridge is too cold. If this situation persists, even if you set a higher temperature, the thermostat is faulty.
Get a fridge thermometer and place it inside the unit. Check it at least two times a day, preferably three, and write the temperatures on a piece of paper. If you notice fluctuations, the thermostat is most likely faulty.
How to Test a Chest Freezer Compressor
Refrigerators aren’t the only appliances that use compressors. Your chest freezer also relies on a compressor to keep your food frozen. Here’s how to troubleshoot your unit.
1. Check the electric circuit
Make sure that your chest freezer is plugged into an appropriate circuit. If it is, check the circuit breaker and fuse box for any signs of malfunction.
2. Check the evaporator coil
Take off the guard plate at the back of the freezer and inspect the evaporator coil. If it’s covered in ice and your freezer is the self-defrosting type, you might have to replace the evaporator coil. Otherwise, it is a sign that you should defrost and clean the freezer.
3. Pay attention to any strange noises
Like refrigerators, chest freezer compressors hum or buzz when they run. However, this noise isn’t disturbing, and you may not pay attention to it at all throughout the day. If the freezer produces a loud humming or buzzing that distracts you, it is a sign that something’s wrong with the compressor or the condenser fan.
If it’s the condenser fan, a cleaning might solve the problem. However, you’ll have to replace the compressor if it’s the culprit.
Do you still have questions? Check out the answers below.
What is a fridge compressor?
A compressor is the heart of a refrigerator responsible for circulating the refrigerant throughout the system. It also adds pressure to the warm part of the circuit and heats the Freon, turning it from liquid to gas. As it passes through the coils, the Freon cools down and condenses, turning into its liquid form again and cooling off the fridge.
How often should a fridge start and stop?
Most refrigerators run for four to eight hours straight before shutting off and going into defrost mode. The off-time lasts for about 30 minutes; then, the compressor starts again. Depending on how often you open the fridge door and the set temperature, it should cycle on and off about four or five times a day.
How often should a freezer cycle on and off?
Freezers aren’t that different from fridges; that’s why your freezer should also cycle on and off about four to five times a day.
A compressor that starts then stops immediately is always a sign of trouble, but the problem is sometimes as easy to fix as setting the right temperature from the thermostat or replacing a faulty thermostat. If the problem is an inadequate circuit or a broken compressor, you should call in an electrician or have the unit repaired by a professional.