No wonder three way fridges dont work
Submitted: Sunday, Feb 25, 2007 at 16:54
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skulldug
At the
Adelaide Caravan and Camping Show yesterday, I asked the guy at the Dometic stand why my 3 way fridge doesn't work. He sold me the usual line about bad installation, so bought a fan kit off him.
Well, no wonder the things don't work! This is a really poorly designed fridge for Australian conditions and very badly installed by the popular caravan manufacturers. Read on if you want to be bored by what I think is the solution.
When I removed the fridge to fit the fan, I could see it all relies on an absorption unit and condenser at the back. It is inside the caravan so when it gets hot, the heat generated circulates inside around the fridge. I don't think its good enough to fit a computer fan onto the vent. The fan needs to be fitted on the back of the fridge between the absorption unit and condenser blowing air upwards. Next, bend some aluminium to direct the hot air out of the vent.
With this mod, my fridge got down to -C6 over night and stayed there all day! It normally takes two days to cool the thing down to +C4.
Next van I buy will have a couple of Engels (OK - or Waecos) mounted side by side.
Cheers
Doug
Reply By: Motherhen - Sunday, Feb 25, 2007 at 17:42
Sunday, Feb 25, 2007 at 17:42
Hi Skulldug
When we had a camper with a gas only fridge we never lit it (big bang theory paranoia). Just used it like an esky - open in the cool of night and closed during day. They work on the same principal as the old kerosene fridges we had when i was a nipper, which were very efficient, even if they did catch the floor on fire occasionally.
We bought an old small wind up van with a three way which the guy assured us was OK even if slow to cool on electricity but he never tried it on gas. It didn't work at all (assessed by fridge repair man). We got a beaut Engel front opening 12/240 volt fridge to fit into the same spot; has small internal freezer compartment. Works really
well. Around same size as the 130 litre Vitrifrigo in our present caravan.
For around $2g i recall, we got the Engel, a solar panel, deep cycle battery, power level monitor, and 12 volt lights. That was 4 or 5 years ago.
We don't have that caravan now, but my daughter and her family are using it.
If you can afford to change over, go for it.
AnswerID:
223895
Reply By: WWAB - Sunday, Feb 25, 2007 at 18:18
Sunday, Feb 25, 2007 at 18:18
Problem with 3 ways is uneven temp, my old 3 way would freeze the salads, and when traveling on 12v didnt run to
well.then on hot days 36+ temp. it was crap.
Now have a engel SRE-90 cost $1000. & runs A1, with two AGM batteries in the van will run for 4-6 days - charge up while touring or if stopping at caravan park for supplies or run geni for a few hours with large battery charger.running geni works out cheaper than gas for the old 3-way. Do a lot of
bush camping on uneven ground not to fussy about being dead level now.
WWAB
AnswerID:
223901
Reply By: Member - Brian H (QLD) - Monday, Feb 26, 2007 at 09:59
Monday, Feb 26, 2007 at 09:59
I have a Chestcold Mark 2 (damn old, was mums). I will say for me I need to get it cold a day out from my trip more if i can that way when its on 12 volt it will be fine at my night stop to which I hook up the gas and run it on gas for the night.
For me it works bit of mucking around and I would like an Explore or tailblazer but at the moment $2000 is not a option I can go down.
As I don't open it during my drive my food is very cold as is the beer and thats all i can ask :) ............... just got to watch it on gas overnight and turn it down otherwise it will all be frozen in the morning.
The other issue I do have with it, it draws heaps from the battery 12 amp and hour I beleive, it is hooked to a 130 amp deep cycle.
If set up for any period it stays on gas. I am happy enough (cost me nothing).
I will have it for the meet up in SA so it better keep going lol.
Brian
AnswerID:
224001
Reply By: disco1942 - Monday, Feb 26, 2007 at 18:08
Monday, Feb 26, 2007 at 18:08
Doug – you said “It is inside the caravan so when it gets hot, the heat generated circulates inside around the fridge.”
This seems to me like you have an installation problem. This is common problem as caravan builders do not in the main use their own products. Remove your fridge again and replace it together with fibreglass bats at the sides and top of the fridge so that the hot air does not circulate around the sides and top of the fridge.
“Next, bend some aluminium to direct the hot air out of the vent.” There should have been a heat deflector from the fridge case at the top of the heat exchanger that was connected to the top of the vent in the side of the van. Whilst at the show did you look to see how many manufacturers have not fitted this. If you have fitted this when you installed the fan then this will have accounted for a fair bit of your increased efficiency.
The third thing to look at is the spacing of the fins from the wall. If there id a large gap then the air will flow around the fins instead of through them. Pack
the gap so there is only 5mm clearance behind the fins for the whole of their dimensions.
I once had a van that had that heat shield but the top vent was mounted so low that the shield was bent down to meet it. I had another vent installed above the original top one and the heat deflector was replaced with one that reached the top of that vent. I did not have to fit a fan – worked OK without it. There was never a problem with the fridge after that – it just needed a few bits to fix the van constructors stuff up..
It is surprising how many spit the dummy and do not try the installation improvement first. With a little bit of effort they could have saved themselves $2-3K for a new fridge and solar installation.
PeterD
AnswerID:
224114