A refrigerator compressor relay is a vital part of the process of refrigeration. But it can develop problems. So, this article discusses relay issues and how to solve them.
What Does a Refrigerator Compressor Relay Do?
The start relay on a refrigerator compressor is a device that powers and protects the compressor. Typically, the compressor needs a boost of power whenever it wants to start and run. The relay supplies the needed power. And when the compressor draws more power than it needs, the overload relay protects it from burning itself out.
How to Bypass a Refrigerator Compressor Relay
To bypass the relay on the compressor of a refrigerator, do the following:
Disconnect the refrigerator from electric power or power down the circuit breaker. Move the refrigerator a little way from the surface behind it. Create enough space for you to fit and work. Next, remove the panel covering the compressor, coils, and fan.
You will find a metal box on the lower right side of the compressor compartment. Push and detach the box from the refrigerator. When you remove it, you will find the relay there. Using a flat-head screwdriver, press the gap between the case and the relay itself. This action releases the relay from the case. So, remove it and slide its wire out to make the case more accessible.
Now, pull out the connector fixed to the relay, and peel both sides of the connecting wire. Use a pair of pliers to strip it. Connect the stripped wire directly to the case of the relay, without the relay in place. Fix the box back in position and replace the panel over it.
Reconnect the refrigerator to electric power or turn the circuit breaker back on. Allow the refrigerator to run for a couple of hours and observe its performance. If you hear the usual click and hum as the compressor starts, you know the bypass was successful.
Be aware that while it is successful, it is only temporary. Do not overload the compressor so it does not wear out quickly. If necessary, hire an appliance technician to check and fix any further compressor relay issues.
How to Tell If a Refrigerator Compressor Relay Is Bad
If your refrigerator does not cool at all or colls but not enough, the relay may be bad. The compressor may not run due to the bad relay, and if the compressor fails to run, the refrigerator won’t cool.
Listen to the sound of the compressor. It makes a low and quiet hum or buzz as it runs. And a few times, it cycles off for a few minutes before cycling on again. If the refrigerator remains without sound, the relay may be faulty.
Another sign of a bad relay is a clicking noise from the compressor. The relay makes a click whenever it powers the compressor to start and run, whether or not the compressor starts and runs. But if the clicking noise comes repeatedly, with an interval of two minutes between each noise, the start relay is faulty and needs a replacement.
How to Check a Refrigerator Compressor Relay
To check the functionality of a refrigerator compressor relay, do the following:
Unplug the refrigerator from the wall outlet and move it away from the wall. Go to the bottom back, remove the panel over the compressor, and find the relay. It is a small device attached to the body of the compressor.
Pull it out and shake it. The relay should make no sound or rattle. If it rattles, it indicates the relay is faulty. Replace it. And if there is a burnt odor coming from it, replace the relay because it is damaged.
However, if the shake and rattle test does not work, check it for continuity. Place the probes or testers of a multimeter between the relay’s terminal 1 and terminal 2. If you find continuity, the relay is in good working condition. But if you find no continuity, replace the relay.
Another way to test it is to place the relay vertically, ensuring its coil faces up. Then, check for continuity between terminal 3 and terminal 1. If you find no continuity, replace the relay. But if you place the relay vertically, with the coil facing down this time, and you find continuity between the two terminals as before, replace the component.
Electromechanical Relay PW, EG, and F
Place the relay vertically, with the coil facing down, and run a continuity test on it. Place the probes of the multimeter between terminal 10 and terminal 11. If you find no continuity, replace the relay.
But if the relay is vertical, with the coil facing up, and you check it for continuity between the two terminals as before, you should not find continuity. If you find continuity, the relay is faulty and should be replaced.
To test a PTC start relay, get a multimeter and set it to Ohms. Take the red probe and plug its end into the positive terminal on the multimeter’s bottom. The black probe goes into the negative terminal on the bottom.
The ports on the relay are marked with letters. Find the two marked M and S. these are the ports that connect the relay to the compressor. Plug the probes of the multimeter into the slots on the relay and check the resistance reading on the multimeter.
You should see O.L on the multimeter, meaning that the two ports have an infinite resistance level between them. If you see 0 or 1 ohms, turn the relay the right side up; it is upside down. Leave the probes in the relay’s ports while you turn it.
If the reading on the multimeter is between 0 and 1 ohms, the relay is in good working condition. If the reading exceeds 1 ohm, replace the PTC relay. In other words, the relay should read O.L or 0 to 1 ohm.
Before testing the relay, clean the device and all its sports to remove dust. Dust may interfere with the resistance reading, throwing it off. If the reading you get is wrong, clean the relay and run the test again.
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How to Replace a Refrigerator Compressor Relay
To replace the relay on the compressor of a refrigerator, do the following:
Disconnect the refrigerator from electric power or turn off the circuit breaker. If you have clear access to the back of the refrigerator, you can begin working. But if not, move the refrigerator to create space for you to fit and work. You may need help moving the unit.
Next, unmount the screws holding the bottom access panel in place. Remove the panel to gain access to the compressor. The relay is fixed to one side of the compressor. Pull the wire retainer that holds the relay to the compressor off. Now, you can pull the relay out from the compressor.
Disconnect the wire connector from the relay and separate the capacitor from the relay. Fix the capacitor to the new relay and reconnect the wire connector. Connect the relay to the terminals of the compressor and reinsert the wire retainer to secure the relay. Cover the compartment with the access panel, and reconnect the refrigerator to electric power or turn on the circuit breaker.
This video demonstrates how to replace the relay on a refrigerator compressor:
Types of Refrigerator Compressor Relays
There are three types of relays used on the compressor of a refrigerator. There is the positive temperature coefficient or PTC relay, potential relay, and current relay.
1. PTC Relay
The PTC relay employs a positive temperature coefficient sensor to eliminate the starting components from the compressor’s circuit. The wiring of the circuit is such that the sensor lines up with the starting components. When the compressor motor starts, power flows through the starting components and the sensor.
The power heats the sensor, increasing its resistance. The resistance rises to the point where it eliminates the need for the starting components. The motor will be running at this point. This type of relay needs time to cool before you can use it to start the motor again.
2. Potential Relay
The potential relay type employs the start winding’s induced voltage to power the relay’s coil. The wiring of the coil is such that it is parallel to the winding of the motor. Once voltage powers the coil, it opens contacts that were closed. As the motor runs, the contacts stay open. But once the motor stops running, the contacts close.
3. Current Relay
A current relay type employs the first rush of voltage that the compressor draws to power the relay’s coil. It also brings in an additional starting circuit. The relay coil’s wiring is in series with the compressor’s run winding. That way, it can sense that first rush of voltage.
This type of relay has open contacts that are wired to be in series with the compressor’s start circuit. As the compressor tries to start, the contacts close and employs the start circuit. As soon as the compressor starts, the contacts open again and remove the start circuit.
How to Install a Relay and Overload on a Refrigerator
Do the following if you are looking to install a relay overload on a refrigerator compressor:
Pull the refrigerator out from the wall and disconnect it from electric power. Unmount the nuts securing the bottom back panel over the compressor. You will need a quarter-inch nut driver for this job.
You may find a clip that holds the relay overload to the compressor. If you do, take it out using a pair of needle-nosed pliers. Next, reach into the compartment and unmount the relay device from the compressor’s side socket.
Disconnect the wires connecting the assembly to the compressor with the pliers. You may need to take a photo to note where each wire goes. Then, separate the relay and overload and discard them. Next, take the new relay and overload assembly, and connect the wires to the appropriate terminals. Your photo will come in handy here if necessary.
If there was a capacitor on the old relay, and it is still working, attach it to the new relay. Now, tuck the assembly into the compressor compartment and carefully mount it onto the compressor by connecting it to the socket. Make sure it is tight.
Replace the panel over the compressor and mount the screws tightly. Finally, reconnect the refrigerator to electric power or turn on the circuit breaker.
Watch this video for steps to install a relay and overload on a refrigerator compressor…
It is clear that a refrigerator compressor relay plays a vital role in how well a refrigerator operates. Therefore, if you find that the relay is faulty, it is crucial to replace it immediately. If you are not sure how to do it, this article will guide you.
Always purchase a compressor relay using the brand and number of your refrigerator. Some refrigerators are specific in the parts that work with them. Contact the brand manufacturer for replacement parts if they are hard to find in hardware stores. But you may find them online.
Additionally, if you have issues fixing any part of your refrigerator, hire a qualified and licensed refrigerator technician. It may cost you but it saves you the stress of having to replace a damaged refrigerator.
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