4 - Way Fridge?

[master]

Hi, I am having problems with my Dometic 3-way absorption fridge not getting cold enough recently. Done the usual stuff and cleaned the flue and burner and tipped it upside down (really this is meant to help and it did a bit). So it does cool somewhat but not brilliantly and certainly not enough for sunnier climes. So it looks like it might be a new 3-way fridge at around £550 - £600 or a same size compressor one at £750 ish (ouch!!!).

Well I have never been too impressed with the absorption fridge getting cold enough, even with vent fans, so the alternative is a compressor fridge. But we do mostly wildcamping and never have EHU, so even with solar panels I am worried about battery drain over 3 or 4 stationary and dull days (even with 2x110Ahr batteries and 2x90W solar panels). You know that perennial fridge debate: compressor vs absorption and which is better!

So.... here is the thought: Why is there not a 4-way fridge that combines a less efficient gas absorption unit with a 12v compressor? Whilst driving, or on EHU, or when there is lots of solar (and likely the ambient temp is higher)) it uses the efficient 12V compressor, and when there is no freely available 12V power (eg its dark and likely the ambient is lower) it uses gas - which is blissfully silent overnight. Has anyone come across such a unit - sounds to me like it would solve the perennial compressor versus absorption fridge issue and give the benefits of both.

Now.... since I have a self-build van and I fitted a secondhand fridge (perhaps thats why its not working too well - its a bit old and tired), and as chance would have it I could only get a step/ wheel arch fridge. Now that gives me a space under the rear of the fridge and I think I could fit a Waeco CU55 compressor cooling kit in the space and mount the evaporator plate inside the existing Dometic 3-way - again I think it will fit. The Waeco kit is about £350 so less than a new fridge (my existing cabinet is fine) which would be good. All I would need to do is re-route the 12V (which comes from a relay switched by the alternator - so only supplied when the engine is running) and 240V (from EHU) to to the compressor - perhaps do some magic with the solar so the compressor gets 12V when the sun shines - and voila my "4-way fridge". Ok the gas is still not brilliant (and would still need to be lit manually) but probably OK to maintain the temperature overnight and on dull days.

Any thoughts on this slightly wacky idea? Anyone done such a thing? I wanted to sanity check this before I go hack my fridge apart - if I do and it works I will let you know.

BTW the Waeco CU 55 compressor unit is just a stand alone refrigeration unit that has no cabinet and is designed to allow you to build your own insulated box with a evaporator inside - a 'diy kit form' fridge if you like - looks a pretty neat unit.

 

[maingate]

Save yourself some money and try fitting a couple of fans to the inside of the top grille (blowing out of the interior). It usually makes a difference.

 

[master]

Yup already done that - with a thermostat so they only run when its warm. They certainly help a lot but now are not enough to 'solve' the problem.

 

[colinm]

I have a feeling the Waaco unit has to be fitted without taking the pipes off, if so it will need major surgery of your fridge, so check that out.
I would just connect it with manual switch to leisure battery, you'll need to switch the 3 way manually anyway.
You may well need to make a drain for the condensate, especially if you often change over.

 

[hextal]

What other kit do you run?

I've got 2 100w panels and 225ah of battery and have been stationary for several days without flattening the batteries. From memory my waeco cr80 uses circa 20ah in winter use and 30ah for summer, just cos the ambient temperature is different. I have insulated all sides of the fridge to make it more efficient and vented the rear. I don't have any why, so it's all charged by solar and driving, the former is great in summer but in reality is down to next to bugger all in winter.

 

[n brown]

get an old electrolux which you buy after seeing it work. i just pulled a really old one out of the shed,been there about 6 years covered in spider webs and mouse poo, it was freezing water within the hour

 

[Deleted member 207]

I've got an RM184EGI Electrolux fridge, built in about 1984, after servicing it will ice the evaporator on gas in about 4 hours. Its been fitted as per Electrolux instructions - baffles at rear of fridge to ensure air flow over cooling fins - chimney effect, 15mm plywood cabinet just wide enough for the fridge, exhaust chimney - no kinks and angles upwards and exhausts away from windows.

Servicing - clean the flue annually, check the flame/jet is clean (nice blue flame). Clean the cooling fins. Remove the insulating cowl around the boiler tube and check condition of the insulation - glass wool is used in most. Smell from exhaust and/or a lot of condensation indicates that the flame is not burning correctly. Condensation can also cause dust to build up around the jet.

Don't try and clear a blocked jet with anything other than compressed air or brake cleaner, carry a spare jet if the fridge is getting on in age. Only blow compressed air through the jet - blowing back can dislodge the jet from its holder!!!! Been there, done that.

If it stops working look for yellowish crystals on the coils at the rear of the fridge - any crystals then fid a new fridge as its almost impossible to repair and refill.

No visible crystals then its possible that small particles in the ammonia solution coolant have blocked the orifice in the boiler. Turning upside often cures the problem, you should hear a gurgling sound when turning over and you can repeat that quite a few times to mix up the coolant solution.

One of the best things you can do is to start the fridge every few weeks so that the ammonia solution does not settle into phases.

 

[Pauljenny]

I had similar problems after Running on autogas, long term.
The Dometic tech was itching to replace the cooling unit.
He cleaned all the burner parts, tightened the cooling fins inside the fridge and suggested I fit Truma inline gas filters.
Works ok until the ambient temp gets above 25.

Parking with the fridge vents in the shade, with the top one removed helps.
These UK fridges are not set up for prolonged running at high temperatures.

 

[Deleted member 207]

Always found the 3 way fridges to be temperamental until we had the rv for some reason the American fridges seem to really work well unlike all the European motorhome fridges we have had ?
Maybe they are made for hotter climates not really sure ?

Look for a "T" in the model number on Electrolux/Dometic fridges as this indicates a tropical rating.

I'd guess that about 1 in 10 fridges are installed as per the instructions that came with the fridge. I've only seen ventilation baffles fitted on Westfalias, never on camper tailers or caravans.

Have a look at this webpage for detailed fridge fitment instructions and tips Making caravan fridges work as claimed

 

[mossypossy]

I have also been having problems with the cooling of a big Dometic RM7 something fridge.

After researching the seemingly random cooling, will freeze down to -15 in some locations, and then give up in another parking spot, I think the issue is with the way the absorption controls actually work.

Counter intuitive solution seems to be NOT to whack up the volume knob as it gets hotter. This just increases ambient temperature.

Tried it last night at THE very lowest setting and it got down to -10 in the freezer. This will also save on gas.

Also bought two new computer fans (£6) for the fin heat extraction.

More experimentation to be done..........