How to Diagnose and Repair a Fault With a Frost Free Fridge Freezer

When it comes to standard fridge freezer faults, most problems are generally quite easy to diagnose and have simple repairs or part replacements. Frost-free fridge freezers, however, tend to be a little bit more complicated. In this article, we're going to show you how to diagnose faults with a frost-free fridge freezer so you can get your appliance working properly again.

To test different parts of your appliance for faults, you will need a multimeter at hand. If you haven't used a multimeter before, our quick multimeter guide is here to teach you the basics that you need to know.

If you find that there's a faulty part in your frost-free fridge freezer, you'll need to know your fridge freezer's model number to make sure you purchase the correct replacement parts. If you aren't sure what your appliance's model number is, or if you don't know to find it, don't worry. Our article on finding your fridge or freezer model number will get you in the know.

Let's get started. To learn how to diagnose frost-free fridge freezer problems, either watch our video or follow our step-by-step guide below.

Remember, always make sure you switch off and unplug your appliance from the wall before carrying out any work.

Before diving into the potential issues, we're going to explain how the evaporator in a frost-free fridge freezer works to give you a better understanding of the faults that can occur. Despite their name, frost-free fridge freezers do actually develop frost. However, the frost is concealed behind a cover in the back of the appliance. You will need to remove the shelves, the ice box and the back cover to properly see and access the components inside.

With these parts removed, you will be able to see the evaporator at the back of the fridge-freezer. This is essentially a radiator that's cooled by liquified gas being pumped through it from a compressor.

The fan at the top draws air into the appliance and blows the air across the evaporator. Then, because the evaporator is very cold, it cools the air temperature. That air is then distributed around the cavity by the fan, freezing anything that's in there.

On some machines, like the model we are using for this guide, some of the air is also ducted into the fridge compartment and the flow of that cool air is controlled by a motorised flap. It goes in through a duct up at the top and travels down through the fridge, returning through a duct at the bottom (both pictured below).

When you open the freezer door, the cool air escapes and is replaced by the warm and moist air in the room. The moisture in the air settles on the cool evaporator, and that moisture turns into frost as a result. As that frost builds up over time, it's going to affect the airflow. For that reason, there is a heating element fitted beneath the evaporator.

This element turns on around every 16 hours of the motor running, heating the frost up for a little while so that it can melt and drain away through the hole in the bottom.

The most common frost-free fridge freezer fault is a build-up of ice on the evaporator. If evaporator ice builds up, it's going to affect the airflow, resulting in the temperature never getting low enough. Causes of this could be a faulty heating element, a faulty sensor or fuse, or a fault with the control board or timer. Let's first look at the heater.

To test the heater, you'll need to trace its connections to the plug. On the model we're using for this guide, the wire goes from the heater, up the side of the evaporator, and behind the fan to a plug into the ceiling of the freezer.

You'll need to disconnect the heater from the plug and tests its resistance with a multimeter. You're looking for a reading of somewhere between 200 and 300 ohms. A reading outside of that range will indicate the presence of a fault, meaning you will need to replace the heater.

Now let's look at the sensor or fuse, which is located close to the heater. A working sensor or fuse should get a reading of a short circuit of less than a couple of ohms. Again, any reading different to that would indicate the presence of a fault, meaning you will need to replace the sensor or fuse.

There may also be sensors around the evaporator. For that, you should be getting a reading of anywhere between 2000 and 40,000 ohms. Once again, a reading outside of this would indicate a fault.

If you've checked all of the above areas and found that the parts are working correctly, the most likely source of a fault will be the control board or timer. In this case, these will need to be replaced.

Some manufacturers of fridge freezers are aware of an ice build-up that can occur above and below the evaporator where it's not actually heated. If you contact your manufacturer, they may be able to tell you if your appliance requires a modification in order to prevent this issue from occurring. There may also be further information about how to deal with this and similar issues with your frost-free fridge freezer in your appliance's user manual.

And there you have it! How to diagnose frost-free fridge freezer common faults. Hopefully, you've now gotten to the bottom of the problem and have what you need to return your appliance to working order!

However, it's important to know that there's more to maintaining your fridge freezer than replacing faulty parts. You should also make sure you keep your fridge freezer clean to get the best performance and reduce the likelihood of faults. Our article on how to clean your fridge will teach you everything you need to know.

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