Tuesday 20 June 2017

Fridge not performing well on gas in summer?



Come the summer, that's when classic fridges start to fail! Quite often it is the performance on gas that suffers. The reason for this is that the gas system is a more complex mechanism than the electric one. The 240v mechanism is a simple heating element in the chimney, and basically it either works at peak efficiency for life, or it just fails completely and is easy to diagnose.

The gas system on the other hand relies on the gas being metered through the tiny hole of a jet, and then burning cleanly in the burner. There is also an ignition system, and a safety thermo couple, all of which can go wrong.

But the commonest fault in summer is that the fridge simply doesn't perform as well on gas as it does on 240v, and this is a reasonably sure sign that the gas system is not generating as much heat as it should, or that the heat is not being convected away fast enough because of the hot weather. A camper 3 way fridge is a very different animal to a domestic compressor fridge - ambient temperature and heat movement is much more important.

If it was working reasonably ok before the hot weather, then that's a definite clue. A small computer fan mounted on the inside of the top vent, blowing out, is a great improvement. Also try and see what side of the van the sun is shining on - it gets really hot in there - any sort of sun shade you can rig up is a good temporary fix. The other thing to do is to check the fridge early in the morning - if it has cooled nicely overnight, then that's another clue. Repositioning the van in the shade is often a good idea if it's possible.

If you are still sure that it is working better on mains than gas, then you need a burner service, to make sure that there is a decent flame. Usually the commonest fault is that debris is resting in the burner and interfering with the flame. That's why many people are suggesting blowing out with an airline, but for this to be effective you really need to take the tin box off from around the burner. The next most likely cause of a low flame is smaller debris becoming lodged in the jet, which has a tiny hole in it, which restricts the flow of gas. In order to get at the jet to blow it with air, you need to remove the gas feed pipe, and on no account should you touch the jet with anything metallic like a pin - the hole in the jet is precisely engineered and enlarging it by accident leads to carbon monoxide tragedy. 

Another easy check is to remove the tin box around the burner, and then in the dark, examine the flame - you just can't see it during daylight, but you can in the dark! You are looking for a mainly blue flame at least the size (but NOT the same yellow colour!) as a candle flame - about 30mm. It should also be making a nice gentle sound, like an old fashioned gas light (if you are old enough!). You should also feel heat coming out of the flue at the top. A visual check of the flame at night is often a really good idea, especially if you do it before and after cleaning or service work.

There are plenty of DIY instructions online, but if in any doubt go get it done professionally.

Fridges in general ...

You can't expect too much from a 25 year old fridge. It is amazing that they last so long. I have lost count of the number of times I have seen people come online with fridge problems in summer. British summers are not particularly hot, so even a fridge in need of a gas service will work OK in spring. But as soon as the temperature gets hot - up above 25 and 30, then the fridge just won't cope. It's even worse if you are heading abroad on a well planned and anticipated summer holiday. Nothing ruins it worse than a complaining fridge. So try and get your fridge checked before you go, or at least keep an eye on it the first hot weekend you get at home.

Don't load a basket of new shopping into an empty fridge and then switch it to 12v for the journey, and expect it to be cold when you get there. Have the fridge pre-cooled on gas the day before. Only load it with stuff pre-cooled from the supermarket fridges, and keep ambient food to a minimum. The 12v system is not as powerful as 240v or gas - it's only for maintaining the temperature while travelling, not for cooling or freezing. 

Give an old fridge every helping hand you can - those blue plastic freezer blocks that you freeze and put into cool boxes are a great idea. You can freeze them at home, and put some into the fridge when you load it up. You can also re-freeze them overnight in the fridges tiny ice box, if you are lucky, and then put them in the main compartment during the day. Campsites will also re-freeze them for you.

Keep your visits to the fridge short and sweet. While you are trying to choose between gin and tonic or rum and coke with the door open, you are losing cold!

Consider buying a new fridge! After 15 years and many episodes of learning and frustration, I finally chucked in the towel a few years ago in an Austrian heatwave and bought a new fridge. It was eyewateringly expensive - a thousand euros. But I discovered that technology has moved on. The insulation is thinner, so the walls are thinner and the interior is bigger. It even makes ice - solid cubes of it, rather than pools of water with a bit of ice on top. It is so good that we have to turn it down in cooler weather. If you use your van a lot, it is a good investment, and should last another 20 years.

(Note for Classic Hymer owners - pre 95 Hymers have 50mb gas pressure - modern fridges are now 30mb - you MUST have a pressure reducer fitted if you buy a new fridge)

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