Replacing absorption fridge with compressor model

[oldieish]

2001 Flair 7100i. Finally despair of doing anything with the fridge/freezer - Electrolux RM 6505 aes, original equipment so had a reasonabe run. Increasingly unreliable through to the current state of inactive more often than not. Gas supply works and a decent flame can be seen (cooling not guaranteed); 12v whilst driving not. Guessing the unobtanium pcb to be the culprit. Intend to replace with a compressor model (recommendations appreciated). Either (a) I have a go at installation; or (b) I find somebody who knows what to do and ask them. Attached is a picture of the wiring. Without checking fully I assume the black coated wire is the 12v supply and the white coated wire 240v mains.

For the purpose of information solely:
Is it a case of removing the old fridge, tidy the void, blank-off the gas supply, secure the 240v wiring, fit the new fridge and attach 12v supply to new terminals?

Incidentally if anyone would like the old fridge/freezer please let me know.

 

[GeoffnDee]

The black covered wires look like 240v and the white covered (red + black ?) 12v which should be the supply from the starter battery and alternator D+ signal will not be what you want if you change to a compressor fridge (the leisure battery may then be used as a 12v power supply with D+ signal not needed).
A replacement for your RM6505 (discontinued 2003) could be a Dometic RMD 10.5T but this is an absorption type ,www.jacksonsleisure.com may be able to help with a replacement Dometic or Thetford compressor fridge and advise you which would fit

 

[GeoffnDee]

Also ,It may not be a PCB problem causing the 12v operation not to be working, the , cheap to replace , 12v relay in the photo may be the cause of it not operating as it should on 12v (engine running) if it is faulty or the fuse for its 12v power supply is blown

 

[Bolti]

I have a Vitrifrigo 90L works really well but you will need at least 2 batteries.

 

[Vikdikdok]

Do it ! I changed from a 3 way to compressor fridge . . .
Result, it works perfectly every time and cools/freezes down to -12 (if I use the high setting even when the outside temp is in the '80's

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[Dave Scadding]

12v relay in the photo may be the cause of it not operating as it should on 12v (engine running)

Geoffndee can I ask you for some advice as you appear to know what your talking about. My Domestic 3 way fridge has stopped working again on 12v . I have changed the relay in the engine compartment twice now with 30a 5 pin which was fitted when I bought the van ( Swift Kontiki). It works fine for a while then goes haywire giving false ABS light on dash, radio cut out then fridge no longer works on 12v. My question is, should the 30a relay be bigger ie 40a ? Maybe it’s just burning out?? Any advice would be appreciated.

 

[Lenny HB]

Richard n Ann did a thread recently on converting a 3 way fridge to compressor. A good option as the van remains standard.

 

[Richard n Ann]

Converting our 3 way fridge to compressor.

Been trying to keep busy over the last 2 days so I started my compressor project. Mainly to save gas and the inconvenience of filling up, the compressor fridge will run off solar easily but even if the battery gets a bit low you can fit a resistor to the controller so it will switch off at 11v...

www.motorhomefun.co.uk

Uses 12ah over night now when it's hot weather, still OK

 

[GeoffnDee]

Dave Scadding PM sent

 

[jongood]

The Fridge freezer in our 2003 clou was replaced about 5 years ago with the RMDt8505 which also aren't without their issues. I ve pondered replacing with a compressor model but think I would go for as large a fridge as I could and put a small freezer somewhere else. because I think a chest freezer even a small one is a better idea.

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[Sheddy]

I have recently replaced our Dometic tec tower with a compressor unit and a top oven.
The "new" 12v supply is 6mm twin direct from the leisure batteries with a 15a fuse and isolation switch.
It has worked very well in the recent hot weather and seems draw fewer amps than I expected.
There is an issue with the oven, noisy cooling fan, but a Thetford techie is booked to fix it under warranty.
Jackson's leisure have been great with the supply and support.

 

[activecampers]

The existing 12v feed likely won't be up to the job.
It'll either be controlled by the "engine running" feed, or will be low current just for the electronics.
(3 way fridges only run on 12v with "engine running" or have a low current 12v feed for the electronics (like gas ignitor).

Compressor fridges need beefy 12v cabling to the habitation electrical supply, fused and ideally switched. Even though compressor fridges may be rated at, say, 45w/60w (4/5A) suggesting thin cables are fine, they actually need thick cabling as the compressor start up will have a spike that draws more power, and the voltage drop at that instance can cause compressor to stall or detect low battery when it isn't. 4/6mm2 cable depending on length (RTFM) for live and return. Ensure plenty of ventilation around heat exchanger - having externa vents for the old fridge will help - but also consider fans to blow out in hot summer months.

Gas should have an isolator valve, but yes, also cap it clearly

240v see where it goes - may be to its own breaker or junction box. Just be careful, obvs.

 

[EuroTrotters]

Redundant Hymer TV Cupboard Now a Freezer

So, the Old CRT TV Cupboard, with turntable and up and over door. No longer required. Fridge is small, not great and the freezer even more useless. Turntable removed, door modified and hey presto, better use with refrigeration. TM So, the Old CRT TV Cupboard, with turntable and up and...

www.motorhomefun.co.uk

 

[Richard n Ann]

When I did my compressor conversion I used the thick 12v cable for the 3 way fridge, I found the other end in the fuse box, connected it to the fridge control fuse and uprated the fuse

 

[tonyidle]

Do it ! I changed from a 3 way to compressor fridge . . .
Result, it works perfectly every time and cools/freezes down to -12 (if I use the high setting even when the outside temp is in the '80's

My rm8505 tech tower managed -13 in an outside temperature over 30 last week.

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[Dave Scadding]

Dave Scadding PM sent

Thanks for your time and help Geoff. Very much appreciated, a true gent.

 

[Sheddy]

Ensure plenty of ventilation around heat exchanger - having externa vents for the old fridge will help - but also consider fans to blow out in hot summer months.

The Thetford fridge freezer we fitted is designed to vent internally, we initially left the old vents covers open but the draught through the van fridge vents and internal fridge grills was very strong especially in windy conditions and would definitely not help the heating in colder months. The fridge has performed very well in the heatwave easily maintaining -15°C in the freezer. It may help to vent externally in very hot weather to reduce the temperature in the van but I don't think even in extreme heat the fridge would contribute too much extre heat inside the van and that would vent through an open Heki. On the other hand unvented in the winter may help contribute a little to the heating.

 

[Nigel-ph]

When I did my compressor conversion I used the thick 12v cable for the 3 way fridge, I found the other end in the fuse box, connected it to the fridge control fuse and uprated the fuse

Not sure what you connected the other end of the fridge’s alternator feed to (fridge control fuse?) but it really needs to be connected directly to the leisure battery and by heavier cable than used for the absorption fridge 12v heat source (to cope with in-rush current as the compressor starts). Also, if you have connected to the 12v leisure circuitry somewhere it might be disconnected from the leisure battery when the engine is running (at least it is in my older MH). If it was not disconnected the alternator would deliver at least 14v into the 12v rated equipment. Maybe your MH is wired up differently to mine but it’s worth checking the fridge still has power with the engine running!