Electrolux RM4200S

[Marcl]

So I bought this T4 Reimo conversion (converted by Ava Leisure apparently) a year ago.
It has a 3 way Electrolux RM4200S.

On 12v it was doing nothing when driving. I since found out the ignition line feeding the relay to close the circuit was dud, so fitted a new wire and the relay closes now and the fridge is a "bit cold" on 12V after a 4 hour drive.
On hookup it's a little bit colder, but not by a huge amount. There is never any noise. It's almost impossible to know if it's on.
I haven't tried the gas for long periods to know if it's any better.

Is this normal? Do I have unrealistic expectations?
How easy are these things to service, is it likely I need to clean something up. Replace something?
I asked a conversion place locally if they would look at it and they just replied with "it might be in the way out". Not helpful.

 

[mistericeman]

12v will only 'maintain' the temp whilst driving...

It's a small AND power hungry element...

Not designed for primary cooling.

 

[winks]

Is it doing any better on gas? Gas usually gives the best cooling effect in absorption fridges and it is unrealistic in the current temperatures to expect everything to work well on either electric supply. Make sure the back of the fridge is clear of obstructions to allow a good air flow over the radiator. In old fridges it can be useful to take the fridge out completely and turn it upside down for a day or so. It redistributes the cooling medium apparently.

Cheers

H

 

[n brown]

they're often not great on 12v and 240 and usually pretty good on gas .the idea is to leave it on 240 for several hours before setting off , then maintain that coolness on 12v in transit , then get it on gas when you arrive . freezer blocks will help it cool down on 240 .yours sounds normal enough

 

[n brown]

on gas from warm ,i'd expect it to take 3-4 hours to freeze water

 

[Canalsman]

First off absorption fridges don't make a noise. Compressor fridges do.

As mentioned above 12v is incapable of cooling such fridges. Indeed it isn't really capable of keeping them cool very well either. This is not helped by the movement of the vehicle.

Mains and gas should work equally well assuming that the gas burner is working well and the flue is clean.

These fridges are slow to cool down.

If you're testing it in the current high temperatures the fridge will struggle.

Typically absorption fridges cool to 20 degrees below ambient. So if it's 30 degrees outside it will probably only cool to 10 degrees which is barely adequate.

Wait till it's cooler and try again on mains or gas.

 

[Pauljenny]

This is the hot season.
Fridges struggle to keep cool.
Every time you open the door, you add heat.
There are many, many threads on here, over the years.. Take time to plough through some.
They usually start in July and end in September. You'll get the drift.
Buy a cheap thermometer.
It'll keep you aware that food might be liable to spoil.
Try and run at 3 degrees.
That should keep you safe.

 

[trevskoda]

Thank heavens i went the electric road with a smart inverter,stays at 2c 24/7 on two 90ah batteries and 200w solar.

 

[Minisorella]

As above, I always have the fridge on hook up for 24 hours before a trip. 12V keeps it ticking over for the journey. On gas, I'm sure my over-enthusiastic little fridge could freeze hell over

 

[in h]

Typically, a three way fridge will use about 250watts on gas, 200 watts on 240v and 100watts on 12v.
It is best to give them at least 12 hours to cool down, preferably 24, on gas or on mains before using them.
In hot weather, considerable amounts of heat can build up behind the fridge. It helps an enormous amount if you add two or three fans to pull hot air out if the top vent.
No need to buy fancy expensive ones: get cheap computer cooling fans. They run on 12v, but they run more quietly if you wire them in series from a 12v supply.
Simply cable tie them to the inside of the vent.
Until you can do that, simply remove the vents. The hole won't look neat, but it will let the heat out better.

 

[harrow]

Typically, a three way fridge will use about 250watts on gas, 200 watts on 240v and 100watts on 12v.
It is best to give them at least 12 hours to cool down, preferably 24, on gas or on mains before using them.
In hot weather, considerable amounts of heat can build up behind the fridge. It helps an enormous amount if you add two or three fans to pull hot air out if the top vent.
No need to buy fancy expensive ones: get cheap computer cooling fans. They run on 12v but they run more quietly if you wire them in series ROM a 12v supply.
Simply cable tie them to the inside of the vent.
Until you can do that, simply remove the vents. The hole won't look neat, but it will let the heat out better.

Its been stupid hot down in London and even my home freezer has an extra fan to try to get rid of the heat

 

[Canalsman]

Typically, a three way fridge will use about 250watts on gas, 200 watts on 240v and 100watts on 12v.
It is best to give them at least 12 hours to cool down, preferably 24, on gas or on mains before using them.
In hot weather, considerable amounts of heat can build up behind the fridge. It helps an enormous amount if you add two or three fans to pull hot air out if the top vent.
No need to buy fancy expensive ones: get cheap computer cooling fans. They run on 12v but they run more quietly if you wire them in series ROM a 12v supply.
Simply cable tie them to the inside of the vent.
Until you can do that, simply remove the vents. The hole won't look neat, but it will let the heat out better.

Attaching the fans to the inside of the vent is not the optimal solution.

Ideally you need a baffle with cut-outs. Without that the fans draw air from round their edges and recycle it.

 

[in h]

Generally, three fans will completely fill the vent area, but if they don't, you're right: a baffle helps.

 

[Deleted member 77519]

Don't make my initial mistake and leave the winter covers on the vents, !
Then wonder why the fridge wasn't getting cold. I put freezer packs in mine when setting off on a trip, to help things cool down initially. Might try the cooling fan hack.

 

[Markd]

FWIW my Dometic 7501 fridge freezer has 220w on mains 175w on 12V and 360w on gas.
I find that it performs perfectly well on 12V when travelling - I've not measured temperatures but with a steady input and no opening (because we're travelling) I don't consider the relatively low input as an issue.
If you have problems with 12V operation it may well be worth checking the voltage being delivered at the heating element.
For me 175w is a nominal 15A and under load the terminal voltage drops from 14.2 to 13.5V - this is just acceptable.
With probably 7-8m between the battery and fridge it really needs 10mm² cable to limit the drop to 3% rather than the 6mm² provided by Bessacarr.
Anything more than 1V drop between battery and element is going to hit performance I'd say and an upgrade is desirable.
You don't have to replace the existing cables - running the same again in parallel will half the voltage drop.

 

[in h]

I have a temperature logger in my fridge. You can't detect any difference between power sources, though you can see when a supermarket full of stuff gets put in.
If there is voltage drop on the 12v supply, I'd be looking for poor contacts, not losses in the cable.

 

[Markd]

Certainly checking connectors is a first step and it's free
Shortly after I got my van I noticed that 12V cooling wasn't working, before buying a new element I checked the voltage - zero!
Going under the bonnet I eventually found a 'melted' relay - replacing that restored cooling.
Doing that by default sorted connections at the front and I'd already refixed those on the fridge as part of the voltage check.
As this relay carries a biggish load I now pack a spare relay just in case and being 'standard' could come in handy elsewhere if needed.
From what I've seen on my van the converters aren't generous on cable sizing (my Truma had 0.5mm² instead of the 2.5mm² specified!)
I've also uprated the supply to my cooker hood which as it has a 30w fan and 2x10w bulbs as standard need a bit more than 5m of 0.5mm² to stop the lights dimming - or not working when I put in LEDs first!

 

[in h]

Half of the problem is silly specifications. If Truma specifies 2.5mm when the maximum current is around 6.5A for a short time, average around 1.4A, that really is a bit daft. The makers will have tried different thicknesses and decided what is good enough to work reliably. seems like they reached different conclusions.
2mm would give less than 5% drop over 10 metres at 6.5A so going to 2.5mm would be a safe choice.
0.5mm would drop a little over 2v at 6.5A. However, if a little over 10v is enough to power the Truma (error 44 is only triggered when the voltage falls below 10v), is this a problem?

 

[argoose]

I always thought my 12V supply was not working, but after installing solar panels to maintain the batteries charge state the 12v supply works well. I guess that if the batteries are charged the alternator sends most of its power to the fridge, as it's not needed to charge batteries. After a couple of hours driving, the element has a light coating of frost and the ice in the ice box is still frozen enough to use in drinks. Two hours and fridge is ready to use. Only put pre chilled/frozen stuff in fridge.

 

[in h]

If the alternator is adequate, it really shouldn't make any difference.
The alternator regulator ought to be able to supply the 15A to the fridge, 15A to the SCR (that's about all you will get) the 20A to the starter battery and the 15A to the vehicle systems when running. That all adds up to about 65A and even a small alternator ought to be fine with that.
Of course, it isn't enough to properly charge the leisure bank, but that's another discussion.