fridge installation

Submitted: Sunday, Sep 09, 2012 at 17:57
ThreadID: 97927 Views:1791 Replies:4 FollowUps:1
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Hi all,
over the winter I gave our ancient Newlands van a makeover, including fridge replacement. The old one you could make bread in the cupboard next door it was so hot and things were only just cool enough inside, so out it went for a secondhand Dometic RM2455. After our last trip in 40 degree conditions and complete failure of the old fridge I did a bit of net research to help me with optimal installation, one of the things I found said to connect a couple of laptop fans via a thermal switch to get the hot air exhausting on hot days. It said to use a 70 degree switch and place it on the condensor tube. All done, and we are finally off for a field test next weekend. It occurred to me that I had only run the fridge on each power source for a few minutes to confirm that it worked so today I ran it on gas all afternoon, when I checked it I was surprised to see the fans running. 17 degree air temp, demo beer was drinkable temp, fridge cabinet was slightly warmer than room temp I thought- nothing like the old faithful- the condensor was hot but not burning to touch and my guess would be around the 70 degree mark so my question is the switch in the correct place? If you look from front it is on the left hand side of the condensor at the top turn from where it comes up from the bottom.
Thanks
David
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Reply By: Bob Y. - Qld - Sunday, Sep 09, 2012 at 19:46

Sunday, Sep 09, 2012 at 19:46
David,

If the gas flue is on the left hand side, then I would put the thermal switch on the opposite side. The amount of hot air coming up may give a false reading to the switch.

Even if you lowered the position of the switch, say 100-200mm below the top of the flue, then it should be more accurate.

How about a higher thermal switch, say 100 or 110 deg, slightly higher, for when it really gets hot, and to switch on the 2nd fan?

Could always put a toggle switch in too, to override both fans?

Bob.

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Can't remember most of it.

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AnswerID: 494597

Follow Up By: Bob Y. - Qld - Sunday, Sep 09, 2012 at 19:50

Sunday, Sep 09, 2012 at 19:50
Forgot to say, David, that was some discussion about this subject,on this site many years ago. Try between 2003 - 5, in the archives.

Bob.
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Reply By: mac3 - Monday, Sep 10, 2012 at 08:29

Monday, Sep 10, 2012 at 08:29
Thanks Bob, I think that's where I got my info from initially, but I'm sure the photos showed the switch at the flue side. I'll start by changing the switch to the other end. I recall the poster saying that he had sealed the cabinet so well that even in the high 30s the fridge was working fine and the fans had not switched on. Thanks for your advice.
David
AnswerID: 494618

Reply By: mike39 - Monday, Sep 10, 2012 at 08:55

Monday, Sep 10, 2012 at 08:55
Hi David.
I battled with a Dometic 3 way in high ambients before I called it quits and installed a compressor fridge.
However I did get some significant improvement from the following:

1/ The exhaust flue was not directing the hot gas to the outside of the van vent. Required an angled extension (which should have been fitted in the first instance)

2/ Filled all the areas, sides/top of fridge with packed wool (wife is a spinner so plenty available). Wool is a good thermal insulator.

3/ I installed 3 x 75mm. computor fans on a frame across and directly under the condenser fins. I then baffled the area around the fans with flexible al. insulation sheet (which causes all of the rising cool air to pass through the condensor) and also made up a curved top baffle to direct hot air to the outside through the vent.
The fans were controlled by a 70* thermo switch similar to what you have. The switch was fastened with good contact to the fins close to where the tube comes from the boiler housing. (r/h side)
The fans would cycle on and off during the day, staying off after about 6pm then cycling again from about 9am.

4/ I removed the fin assembly from the inside rear wall of the cabinet. Over time condensation had caused some gunk to form where the contact between the fin plate and the secondary cooling tube should have been very tight. I used some thermal grease (computor repair shop) to create a better thermal connection on reassembly.

All this helped in overall performance, but at its best was no where near as efficient as the now installed Engel van fridge.
Hope there are some ideas for you here.
Mike
AnswerID: 494620

Reply By: mac3 - Monday, Sep 10, 2012 at 10:10

Monday, Sep 10, 2012 at 10:10
Mike, I can see this is dear to your heart! I've pretty well done everything you've suggested apart from the fans on the fins, have used fibreglass wool though. Also have a Waeco compressor fridge in the car :)
AnswerID: 494624

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