Guest 1footinthegrave Posted July 21, 2013 Share Posted July 21, 2013 Following on from an earlier post with folk complaining about fridge performance in hot weather abroad, it has been a Godsend to be able to sort mine out, with temps here peaking at 33c. There is plenty of advice about installing a computer fan to help efficiency, something I've meaning to do for sometime, but on our last trip it really was becoming a pain in the proverbial. Every time I've thought about doing something when back home, I have thought it would be difficult to evaluate any mod I attempted without correspondingly high temperatures, well I'm happy to report mission accomplished, could it help others I wonder. Reading many forums it always seemed to boil down to poor air circulation, the hot air not being able to get away quickly enough, especially if the fridge had been poorly installed by the convertor mmmmm, no comment. The plan was to put a large desktop fan ( 12 cm one ) of course making sure it is the right way round ! directly behind the top vent, (I know other locations are suggested) my concern being anything obstructing the top vent may just create another problem, so time to try it out. But the thing that has made all the difference is I have used a fan that ships with a temperature probe on a 40cm cable, that will push the fans RPM up as the temperature at the back of the fridge increases. Obviously a switch was incorporated as it would not need to run continuously if the night time temp was a good deal lower. Test day was yesterday, I had the fridge switched off, and the outside temperature was around 30c, put it on gas, switched on the fan ( absolutely negligible battery consumption, did not even register as a current draw at all, four hours later fridge was down to 0 degrees, not a hope in hell of that when on our last trip, it remained at that temp for the rest of the day, despite the interior of the van being a blast furnace with all the windows closeed, evening time I switched the fan off altogether. Today quite early popped out to the van and switched the fan back on, opened the door of the fridge a few times,as if on the breakfast run, turned the stat up to half way, and despite today being even hotter as I type it's still down below 0 degrees late this afternoon, and that despite the vents being in full sun most of the day, result. What has really surprised me is it has totally transformed the fridge beyond my expectations,the air movement between bottom and the top vent being very much more noticeable than it ever was before, and being able to test it our in temperatures not normally par for the course at home, so there we are, fairly simple to achieve and a total cost of £8, based on my mod if your having similar issues give it a go, or PM me for more details, I'll be glad to help. ;-) can't stand lukewarm drinks. Ona roll now, Gasit last week, fridge this, and hopefully solar panel next week. ;-) Link to comment Share on other sites More sharing options...
BGD Posted July 21, 2013 Share Posted July 21, 2013 Excellent post.:-D I fitted a dual fan version in our MH last summer, and agree that this mod is dead easy, and absolutely brilliant in practice. I don't know, but assume that it means we use less gas too, as the fan helps a lot to stop the gas system constantly fighting to get the fridge temp down. Why all MH manufacturers don't fit them as standard I don't know. ( Actually I do; it's to save ten quid on build cost). Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 21, 2013 Share Posted July 21, 2013 \thanks for that, yes it's a mystery, like you say, top cost a couple of bob. ;-) Link to comment Share on other sites More sharing options...
Robinhood Posted July 21, 2013 Share Posted July 21, 2013 BGD - 2013-07-21 7:06 PM Why all MH manufacturers don't fit them as standard I don't know. ( Actually I do; it's to save ten quid on build cost). .....they tend not to be fitted by convertors because Dometic don't specify them, as they don't generally think they are a requirement. If a fridge is installed in strict accordance with Dometic's design criteria and instructions, then its performance should be perfectly adequate in all but the most extreme circumstances. Unfortunately, where the saving in build cost generally does arise is in not installing to the required standards (which is annoying, because it is not a difficult task at build time, but can be a pig to rectify afterwards). I have only ever had one van that I would consider had an adequate fridge installation, and that was my last Rapido. It was draught-free, and functioned perfectly well through even the hottest weather. My current Hobby is a case in point. The fridge was poorly sealed from the interior of the 'van, and the upper heat deflector (such as it was) consisted of a misshapen foiled cardboard sheet, which failed dismally to seal anything, and deflected the majority of the waste heat into the upper part of the void behind the fridge, well above the upper ventilation outlet. On our first overseas trip to Slovenia, the 'fridge struggled to maintain a reasonable temperature in the warm weather, and it was noticeable that the worktop over the fridge was getting very warm. I considered fitting a fridge fan, but was concerned additionally about the lack of proper sealing from the interior of the 'van, and the draughts that would arise (being an all-season user). I thus resolved to properly seal the unit edges (using flame-resistant closed-cell tape), and to install a fully sealed heat-deflector to the top of the unit, which was angled (and sealed) from above the cooling vanes to the top of the upper fridge vent (ensuring a direct flow to the exterior) . As the fridge could not be withdrawn, all work had to be done through the upper vent, and to cut a long story short, required removal of the vent frame, and a two-part aluminium plate, butted and sealed in the middle, to overcome clearance problems. A significant amount of work was required to get a full seal, and the required gradient, but I finally succeeded (and when I had reason to have the vent off a couple of weeks ago, I was mildly surprised how neat a job I finally made). The point of all this is that, by proper sealing and providing a heat-deflector roughly to Dometic's specification, not only was the unit draught-proofed, but any need for cooling fans has been completely removed. Even in the recent weather, the fridge has maintained performance on both gas and electric with the temperature control turned no greater than half-way. For anyone who has the appropriate DIY skills, I would recommend checking the standard of installation, and if necessary remediation to Dometic's standards. It has the advantage of removing draughts, and also improving the fridge performance in a "passive" manner. I've already highlighted that it was a pig of a job (the required baffle JUST wouldn't fit without dividing it), so, if maintaining the fridge temperature is the single or main goal, then adding a fan, as above, may well be an easier and more attainable option. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 21, 2013 Share Posted July 21, 2013 You may have read in my post that the fitting of my fridge was less than perfect, so I agree that can be a maor cause of problems once it gets warm, that was obvious when we first purchased the van, with the previous owner making a virtue of the "warm airing cupboard" above it. :-S When we first went out in it during windy weather it blew a gale through the fridge vents into the interior of the van, copious amounts of sealant sorted that out, even the lack of a deflector plate at the rear of the fridge became apparent, that too was sorted, but it still struggled in very hot conditions, well hotter than the Uk usually gets. The fridge however sits further back from the outside wall of the van than Dometic specify, and I think this was the achilles heal, fridge did however work fine until we were in very hot conditions , hence my mod over the last two days that seems to be a success at last. ;-) Must go and check my ice cubes :-) Link to comment Share on other sites More sharing options...
bobalobs Posted July 22, 2013 Share Posted July 22, 2013 Fan is well worthwhile but ours is on a thermostat which seems to vary in its view as to what is hot so may change to an on/off switch. Hope the earlier post of the fridge being 0 Centigrade does not relate to the main body of the fridge as you will be frosting your lettuce! 1 to 5 Centigrade is the fridge thermometer guideline with the freezer compartment considerably colder. I thought the run of the mill fridge reduces the main area of the fridge by little more than 20C from the outside temperature so no wonder they struggle at the moment. Link to comment Share on other sites More sharing options...
lennyhb Posted July 22, 2013 Share Posted July 22, 2013 Don't know if it is down to good installation by Hymer or the newer fridges perform better but this is the first fridge we have had where it performs OK above 30 deg without additional cooling. Sitting on the drive at the moment with ice creams in the freezer, got back late last night couldn't be bothered to unload. Link to comment Share on other sites More sharing options...
kelly58 Posted July 22, 2013 Share Posted July 22, 2013 When we had an Ace Airstream 680FB the fridge freezer was really gas hungry so I fitted two 12v old desktop fans individually switched , so I could have one or both fans on depending on how hot it was the difference it made was amazing. We had a problem with the fridge and Thetford sent a fitter to my home to fix it as we were on our way to France ( that's what you call good service ) when he see the fans he said there are two things I wish converters would do ( 1 ) do as you have and fit cooling fans and ( 2 ) put a door like on the gas cabinet to make working on the fridge a lot easier. Since then I have fitted fans to the rear of all my motorhome fridges. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 22, 2013 Share Posted July 22, 2013 After a couple of PMs thought it easier to post on the thread. Items needed, one Artic F12 pro TC computer fan cost about £5 One switch + plus some crimp blade connectors cost about £2 (There is a thermostatic twin fan unit on the market for around £40) The beauty of this particular fan is that it runs continuously ( when switched on of course ) at 400 rpm, once the sensor detects 32c it increases to a max of 1300, and being 12cm really pushes some air out, supposidly with a six year warrant. As for getting the fridge down to zero which was measured on the bottom shelf, this was obviously just as a test, and as a follow up today is still sitting at that temp with the fridge thermostat in the halfway position to prove the mod has been a success. Remove top and bottom vents, you’ll need to locate the 12 volt supplies to the fridge, one will be coming from the leisure batteries to supply the power for the piezo igniter, and one from your engine battery. The one from the engine battery is likely to be heavier duty cable ( well it certainly should be ) I’m not going to tell people how to suck eggs except to say if you don’t know how to do that much I would not go any further. I mounted the fan on a piece of thin mdf having cut out a circular hole for the fan , having first established where I would be able to fix to behind the top vent cover, to help things along I did it in such a way to leave as much of the vent open for times when the fan is not required in the cooler times of the year. The easiest way to mount the fan on the mdf, was to drill holes in the plastic frame, then secure it using some small pan head screws, with the fan I used you need to have the bulky back part within the fridge cavity. Having identifying the leisure battery supply I simply ( after switching the power off ) cut it and put a screw in cable joiner secured with a screw to the side wall. Then as I have used a switch with a small LED to indicate the fan being on, cut a 20mm hole in a convenient place in the van, took the 12+ battery supply side to the switch, and to the fan, the fan being switched through the 12- neg side, so the supply side neg to the outer connection of the switch I used has three connectors, the centre one being the switched one, you need to establish which of the out two outside connectors makes continuity when operating the switch, then take the negative supply to the correct outer one, and the negative feed to the fan from the other. You could of course just use a two pole switch of course, and a separated led from the fan supply side to indicate it being on. You’ll find the fan has obviously got a connector intended for a motherboard, just cut that off, and trim back the yellow one ( it is not needed, it’s just a signal cable for PC use) the remaining ones being black and red, finally position the heat sensor above the heat fins, or on the heat fins at the top of the fridge and secure with a cable tie, hope that does not sound like gobbledegook, Mike. Link to comment Share on other sites More sharing options...
lennyhb Posted July 22, 2013 Share Posted July 22, 2013 If you think it saves a lot of gas I may fit a couple of fans as we drink gas can get through an 11kg bottle in 2 - 3 weeks in the summer. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 22, 2013 Share Posted July 22, 2013 lennyhb - 2013-07-22 12:40 PM If you think it saves a lot of gas I may fit a couple of fans as we drink gas can get through an 11kg bottle in 2 - 3 weeks in the summer. Lenny, reluctant to tell folk in case the jobsworths come out, but I service my own fridge, if you saw the absolute mind boggling minute size of the jet I doubt I'll save much gas, but who knows it's not going to be constantly flogging itself to death to keep the thing working properly, I'll keep you posted.. ;-) Link to comment Share on other sites More sharing options...
BGD Posted July 22, 2013 Share Posted July 22, 2013 lennyhb - 2013-07-22 1:40 PM If you think it saves a lot of gas I may fit a couple of fans as we drink gas can get through an 11kg bottle in 2 - 3 weeks in the summer. No idea of exactly how much it'd save, but logic says that it should save quite a bit during hot weather if you're parked up and using gas to operate your fridge. In fact even in cooler weather it should still present a gas saving. Anything which means that the fridge gas burner doesn't kick in so often, nor run for so long, will save the gas otherwise consumed. As gas is an expensive fuel, and the electricity to run the little fan/s so as to reduce gas consumption is free (assuming you've got a solar panel, or move around now and then so that the engine alternator re-changes your supplying battery)....then it's really a no-brainer. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 22, 2013 Share Posted July 22, 2013 I might be wrong Bruce, but I think you'll find the burner stays lit all the time, but controlled by the thermostat to produce a smaller flame when the desired temp has been reached, my thinking being if it went out altogether the thermocouple would shut off the gas supply and you would have to start the lighting sequence again, well you would on my fridge. In any event as you say there could well be significant savings on gas, we'll see. ;-) Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted July 22, 2013 Share Posted July 22, 2013 Ooooh! ...Desktop computer fan.... (lol) ...I was wondering how the b**dy 'ell you shoehorned one of those "desk" fans behind your fridge.. ?! :$ (lol) Link to comment Share on other sites More sharing options...
lennyhb Posted July 22, 2013 Share Posted July 22, 2013 1footinthegrave - 2013-07-22 1:39 PM I might be wrong Bruce, but I think you'll find the burner stays lit all the time, but controlled by the thermostat to produce a smaller flame when the desired temp has been reached, my thinking being if it went out altogether the thermocouple would shut off the gas supply and you would have to start the lighting sequence again, well you would on my fridge. In any event as you say there could well be significant savings on gas, we'll see. ;-) Nope the newer fridges are electronic controlled and only light when needed, just stand by the vent when it's running you can hear it light up. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 22, 2013 Share Posted July 22, 2013 lennyhb - 2013-07-22 4:20 PM 1footinthegrave - 2013-07-22 1:39 PM I might be wrong Bruce, but I think you'll find the burner stays lit all the time, but controlled by the thermostat to produce a smaller flame when the desired temp has been reached, my thinking being if it went out altogether the thermocouple would shut off the gas supply and you would have to start the lighting sequence again, well you would on my fridge. In any event as you say there could well be significant savings on gas, we'll see. ;-) Nope the newer fridges are electronic controlled and only light when needed, just stand by the vent when it's running you can hear it light up. There you go then, you learn something everyday, mmmm, years ago there was an inspection window on the front so that you could see the flame, and if it was burning OK, can't see a thing on mine, progress eh. Link to comment Share on other sites More sharing options...
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