A couple of days ago we noticed water in our freezer. In an RV finding water anywhere it should not be can be a sign that you have a leak. My concern here was not a leak but the fact that it was water and not ice. We quickly dried up enough to keep it from overflowing and still keep as much of the cold in as possible. We also noticed that the refrigerator was warmer than it should be which is not strange since it runs on the same system as the freezer. Our unit is a 2-way Dometic fridge and freezer that can run on either 110v electric or propane. Like with any absorption fridge the only way to know for sure that it is working is to check that it is cold inside and that the heating element gets warm. There is no compressor that you will hear running like on most residential fridges. Ours also only has 2 buttons and no other controls.
On/Off and Auto/Gas are the only controls on the fridge.
All we could do was switch it to gas and pray that it would start cooling again. It was late at night so we went to bed not knowing if we would wake up and have to deal with all our food before it would spoil. When I got up once in the middle of the night I found, to my great relief, that it was getting cold again. This meant that we at least didn't have to pay for a repairman to come look at it the very next day. We had the option to run it on gas and try to figure out if I could fix it so it would once again run on electric.
I did some research and found that the most common failure on these kinds of fridges is the electric heating element. The second most common is the control board. I consulted the service manual - Thank you Dometic for making those available for download! - and got very good advice on how to troubleshoot the different parts.
Inside the access panel behind our fridge.
In the above picture, the 2 main things I needed to check are both hidden. The heating element is inside a tube behind the metal cover on the right. The control board is hidden behind the black plastic lid on the left. At this point, I'm really hoping that it is a burnt out heating element because they are much cheaper to replace than the control board. I start by methodically testing all that I know how to test. First and very easy I test the two fuses that I find and make sure that they are still intact. After that, I test that there is proper AC voltage coming into the control board and that it outputs the proper AC voltage to the heating element.
So far everything tests like it should which made it very likely that it would be the heating element since the board both got the right voltage and sent it out. But when I test the resistance of the heating element that also measures like it should.
42.6Ω is within the expected range.
Now what can I do? Everything tests like is to be expected when it's working. There is one more test I can do and that is to set in on electric and see how much current flows through the heating element. If that is within the expected range then it really should be working.
It all tests right, so the final test is to see if the heating element gets hot and the fridge and freezer gets cold. After a couple of hours, it was clear that it now was working again. This is, of course, the best possible outcome and yet it is very frustrating. I was looking for something that was not working and could not find it. It was very clearly not working and did not start working when we turned it off and then on again a couple of times. Something must have happened when I was working in the back.
The big question now is: can we trust it? If the electric fails again, we can still run it on propane but we will have to notice that it is not working and make a manual switch. We could lose all our frozen food if it fails when we are away on a warm day. All we can do is keep and eye on it and hope that it will just keep on working.
In the end, I did learn a lot more about how our fridge works and we did not have to spend money on spare parts or worse, buy a new one.
