Friday, November 25, 2022

DIY Series 29: Basic Repair of Fridge / Freezer

The only difference between a refrigerator (fridge) and a freezer is temperature range. The freezer maintain the core temperature as low as -18 degrees Celsius. For a fridge, it needs to be set at about -6 degrees Celsius to 10 degrees Celsius. As for the electrical / electronic design, it should be almost the same concept to understand the whole system.

Most fridges are having freezer at top / bottom compartment, depends on makers & models. However, only certain freezer can work as fridge, and most of the are solely act as freezer by itself.

Example of Freezer (Hisense Freezer Model FC125D4BWS)

Fridge / Freezer is not so difficult to understand, from the circuit diagram point of view. You can refer to the circuit diagram below to identify the main parts involved. I use the common circuit diagram of a freezer as example:


Main Parts:
1) Compressor (most expensive part in the freezer)
2) PTC (Positive Temperature Coefficient) Starter / Relay
3) Overload Protector
4) Thermostat
5) etc...

If your refrigerator stops producing cold air, there may be something wrong with the PTC Relay, also known as the start relay. The PTC relay starts the compressor inside the fridge to make cold air so your food stays cool. 

Luckily, the PTC relay is something you can easily check and replace yourself if you need to. After you access the relay and compressor on your fridge, use a multimeter to test the ports to make sure it has a low resistance. If the relay still works, you may also need to check the compressor to make sure it’s still functioning.

Accessing the Relay / Overload

1) Unplug your freezer, to prevent any possible of electric shock
2) Remove the lower back / side panel from your freezer to access the PTC Relay & Overload Protector
3) Grab the top of the plastic cover and carefully pull it off from the compressor to expose the relay / overload inside
4) Disconnect the wires from the relay. Disconnect each wire from place so you’re able to remove the relay.
5) Remove the relay by pulling it off of the prongs. The relay should easily slide off of the prongs and disconnect from the compressor so you can test it.

Example of Compressor (inside Khind Freezer Model FZ102)

Location of PTC Relay & Overload at Compressor (after unplug)

Example of Overload & PTC Relay (22Ohm)

Checking the Relay with a Multimeter

1) Look for burnt marks around the ports on the relay to see if it’s shorted. If the relay is still intact, then continue testing it using multimeter.
2) Set your multimeter to read resistance in ohms (Ω) so you can easily test the PTC Relay
3) Put the probes in the M and S slots on the relay to check for open resistance. If the meter has a reading between 0-1 Ω, then the relay is still working. If the reading doesn’t change or it’s above 1 Ω, then it may be time to get a replacement.
4) If the relay has correct readings, then you should check the compressor next to see if it’s causing the problem.

The PTC Relay & Overload parts replacement costs around MYR10 to MYR15. Thus, it is worth to buy it online and have a try if it can solve your problem. Look for the correct parts, as there are many types of replacement parts of PTC Relay & Overload for various fridge / freezer models. 


If after changing PTC Relay & Overload, the fridge / freezer is still not producing cold air, it is highly suspected that the compressor is spoilt. 

To replace a compressor, you will need professional skills and tools. It is very costly, repair guy might charge you from MYR400 to MYR700 for the repair / replacement. For such a cost, you can actually buy a new unit of freezer. Not worth to proceed further repair.

To repair / replace compressor, it is out of my knowledge & capability at this moment. Will look into it in near future.

Reference Price (Brand New Unit):
Khind Freezer Model FZ102: RM499
Hisense Freezer Model FC125D4BWS: RM499

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