How to Diagnose a Fault with a Frost Free Fridge Freezer

Hi I’m Josh from And in this article I’ll be helping you to diagnose a fault in a frost-free freezer or fridge freezer. Now generally speaking most faults in fridges and freezers are very simple to diagnose and actually just involve replacing the faulty parts such as the door seal or the lamp.

However because of how they work frost-free appliances tend to be a little bit more complicated. Now they do actually develop frost but you can see it because it’s concealed behind the cover in the back. To give you a better idea of what’s going on I’m going to remove the shelves and the icebox as well as the back cover so we can see the components inside.

Here in the back we have an evaporator, now this is essentially a radiator which is cooled by liquefied gas being pumped through it from a compressor. This fan up at the top draws air into the appliance and then blows air across the evaporator because the evaporator is cool it to cools the air temperature. And that air is then distributed around the cavity by the fan freezing anything that’s in there.

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Now on this particular model some of the air is also ducted into the fridge compartment and the flow of that cool air is controlled by a motorized flap. And it goes in through this duct up at the top here then travels down through the fridge and returns through this duct at the bottom. Now when you opened the freezer door the cool air inside falls out and it’s replaced by the warm moist air from the room.

The moisture from the air settles on the cool evaporator where it cools so much that it turns to frost. Overtime a build up of that frost is going to affect the air flow. So for that reason there is an element fitted underneath the evaporator which turns on round about every 16 hours of the motor running.

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And for a little while heats all the frost up so that it can melt and drain away through the hole in the bottom and out to the back.

Now the most common faults that occurs in a frost-free appliance is the build-up of ice on the evaporator. If ice builds up then obviously it’s going to affect the air flow and that means that the temperature is never going to get low enough. Now courses of that could be a faulty heater, a faulty sensor or fuse or a fault with the control board or timer.

Now to test the heater youl need to trace its connections to the plug.

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In this particular model the wire goes from the heater up the side of the evaporator and behind the fan to a plug in the ceiling of the freezer. You need to disconnect the heater from the plug and test its resistance with a multimeter. And you’re looking for a reading of somewhere between two hundred and three hundred ohms.

So obviously any reading outside if that would indicate the presence of a fault and you need to replace the heater. You may also developed a fault in the sensor or the fuse which is located near to the heater. Now a working sensor or fuse should get a reading a short circuit (for the fuse) or less than a couple of ohms and again any reading was different to that would indicate the present of a fault.

There may also be sensors around to the evaporator and for that you should be getting a reading of anywhere between 2000 and 40,000 ohms any reading outside of that which explain that there is a fault there and once you’ve checked all of those areas than the most likely sources the fault is the control board or timer and you need to get those replaced. Now in some manufacturers fridges and freezers they are aware of a build up of ice that occurs both above or below the evaporator where it’s not actually heated.

Now if you contact you manufacture they may be able to advise you of a modification that can be done in order to prevent this issue from occurring Now if you need help in diagnosing other problems in your appliances check out our other articles. And spares for fridge freezers along with other appliances are available on the website. Thanks for reading.