Tech Tip number 3587 and a half - Fridge Cooling - Fan - Fridge not working in hot weather.
Well the hot weather is here and I guarantee that some owners of Classic Fridges will be cursing theirs at some point! They always seem to freeze the beer in winter yet it's lukewarm in summer.
The commonest reason for this is that the fridge simply gets too hot. Van fridges work by converting heat to cold, but if the ambient temperature gets too high then the efficiency suffers. Dometic know this, and many fridges have a cooling fan behind them - some owners don't even know it's there, and even if it is, it is usually one of the first things to break, as it is exposed to the elements.
So, to ensure the best chance of cool beer in summer, you need a cooling fan. And if you have one fitted, you need to make sure it is working - and to be honest, the fans fitted on Classic fridges - ie 20 yrs old, are pretty rubbish and should be replaced.
So here is the mod - first you need a fan, and the best types are those that you find inside computers to cool them. They are designed for non stop use, and they are quiet. Ebay is full of them for just a few quid - my advice is buy 2 - one for a spare. All you need extra is some wire, pliers or cutters, and some way of connecting and joining wires - crimp connectors, choc block connectors, or at a pinch - twist the wires together and tape them up (if you really must!)
Take the covers off your fridge out side. Look inside - do you see a fan? If you do, then you need to see if it is still working - some fridges have a manual fan switch, but others have an automatic thermostatically controlled circuit that is supposed to be fully automatic. The only way you can test this is to see if the fan is working in boiling hot weather - but even so while you are at it you might as well either replace it, or fit an additional one.
If an original fan is fitted - it might be noisy, so replace it, using the same wires, with a nice quiet powerful computer fan - but mount it on the inside of the top grille - blowing out - see photo.
Lets assume you have an old fridge with no fan. The easiest way to fit a new 12v computer fan is to simply use cable ties and attach it to the inside of the top grille - and do make sure it is blowing out - not in.
Next - the tricky job of connecting it. Here is where I am afraid I can't give specific instructions, because every van is different. But basically you need to find a wire that has 12v on it, and then tap into it for the fan supply, via a switch. A multimeter will help here - on most vans I have seen there are plenty of wires to choose from hanging around the cavity at the back of a fridge - the standard old Hymer scheme is a black cable, and inside a brown and a blue wire - blue is 12v, brown is ground.
You also need to find a switch, and somewhere to put it. Any switch will do - choose something that looks good and will fit in a convenient place. It is even acceptable to mount the switch externally even on the grille itself if you can't find a place in the van. Some fridges had a fan as standard with a switch mounted on the front panel, but the fan has maybe stopped working after many years. It is quite easy to use this switch and wiring to a new fan on the inside of the grille.
Now for those of you who turn green at the thought of anything electrical, don't give up! This is a very very easy job - so ask around your family and friends for someone to do it - even your local camper van place will struggle to charge you more than half an hour - especially if you supply the fan.
If you are going to DIY, then you will see the fan has a red and black wire. The black goes directly to the brown in the Hymer wire, and the red goes from the fan, to one terminal of the switch, and then from the other terminal of the switch to the blue Hymer wire - geddit? When switch is off - no 12v, when switch is on 12v goes to fan.
Sounds complicated, it isn't! And it is really worth doing if you are suffering from summer lukewarm fridge syndrome.
Next time you are parked up and the sun is beating down on the side of the van where the fridge vents are...just go out there and feel the heat where the grilles are - then you will understand just how hard the fridge has to work in these conditions. With a powerful, but quiet, computer fan installed on the top grille, it will pull cool air in through the bottom grille, over the fridge workings, and out through the top. It makes a big difference.
A computer fan takes very little current - you can leave it on all day - if you do get a flat battery, don't blame the fan - something else is wrong. You can switch off the fan at night if you wish, but as long as the low hum of fan noise doesn't disturb you, best to leave it on all the time if you are in a very hot climate.
EDIT - 2019
I have been running fridge cooling fans for many years now, so it's time for a bit of an update. Basically it works, but how well depends on the age of your fridge and where it is located - ie how much ventilation it gets from its standard installation at the factory. The worst offenders here are rear corner fridges like in the S555 and others. But for what it costs, if you DIY, there is no reason why every old fridge shouldn't have a fan. They usually let you down in a heatwave when you need it most, so best to be prepared.
However there are 2 aspects to fridge fans that you should think about, based on my experiences.
The first is quality of fan. You can pick up 12v computer fans for just a few quid, but I have yet to see one that has lasted more than 2 years. The reason for this is that road dust gets into the bearings and the fan basically dies of old age prematurely. First they go noisy and then they stop.
The second is noise. I like a silent van, and I used to find it very irritating to have the low hum a fan on constantly. You can switch it off at night of course, but you might forget - I always do. Or if the fridge is at the back of the bed and you are sleeping in the front, then you may not hear it at all - every van is different.
There are high tech solutions if you are up for it - you can buy temperature controlled switches that should do it automatically, but it's a DIY enthusiasts job.
Here is the solution that has worked for me. I did some research and found a computer fan online called "Acoustifan" (easy search on Ebay and Amazon). Not only is it quiet, but it also has sealed bearings and is dustproof. I bought one of these 2 years ago for about £17 and fitted it myself, as above, simply cable tied to the inside of the top grille, blowing out. It proved to be much quieter, and sounds today as good as it did 2 years ago, and that's after 2 long winter trips abroad.
However what I noticed over time, was that it could even be quieter - the reason being that because it was directly mounted on the grille, the grille was acting like a sort of resonator - a bit like the surface of a drum. After experimenting I found this to be true, and my solution was to put small bits of foam rubber between the fan and the grille. Now it is almost inaudible and I leave it on all the time.
Finally - don't go OTT! I have seen articles where folk have mounted twin fans blasting out noisily. This is overkill. All you need is gentle movement of air to help the hot air out of the top grille.
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