Fitting an RM123 3-way fridge - HELP!

[Tracy&Andy]

Hi,

We recently bought a second-hand RM123 fridge, and are trying to fit it into our van. The 240V came with a fully fitted plug (so that is ready for hook-up), but the gas and 12V weren't. I have attached a gas hose from the base, to the bottle, but we have to fit the 12V car lighter plug to create a spark.

We downloaded the old manual, and it said a 15 amp wire, with a 15 amp fuse in the plug. This is what we did, plugged into the cigarette lighter socket, but it didn't work, instead the plug began over-heating in the socket, and melted the plastic around the rim!!!

Can some-one please help, as we have looked forward to using a fridge whilst out camping.

What are we doing wrong?

Thanks for your time,

Tracy and Andy

[Smcknighty]

Sounds like you tried to power the 12v cooling element - that's a heavy draw thing..

[Smcknighty]

Yeah read the manual - that's the feed for the 12v cooling with the 15 amp fuse..

[Tracy&Andy]

Thanks for the reply.

Do you know how we should wire it up to the cigarette lighter to run it whilst driving, but not over-heat and melt the plug?

It didn't power the ignition for the gas, either, which it is supposed to. Any ideas where we are going wrong there?

We're getting a bit frustrated!!!

Thanks

[MidLifeCrisis]

Hi Tracy/Andy,

The fridge has/requires two separate 12V supplies.
1) The first is used when the van engine is running and powers a cooling element in the fridge to keep it cool. This 12V supply is usually wired to the van starter battery through a relay and a fuse. The relay is triggered by a signal from the engine alternator so that the relay is only allowing the fridge to connect to the battery when the engine is running. (The relay is required because the 12V fridge cooling element draws a lot of power (as you have discovered!!) so it would quickly drain your starter battery if it was allowed to run when the engine/alternator was not recharging the battery)

2) There is a second 12V supply to the fridge which powers the 'sparking unit'. This can either be connected to the starter battery or the leisure battery (again via a fuse for safety) and provides the power to allow the fridge to create a spark to light the gas supply when the fridge is used 'on gas'. The power requirement for the 'sparking unit' is pretty low so you don't need to worry too much about this draining the battery (although most folks connect it to the leisure battery so that this isn't an issue).

You could try reading some of the stuff on this page in the Wiki (especially the bit at the bottom of the page about fridges);
https://club8090.co.uk/wiki/Ca ... it_charger

Also, as a final thought - why did the fuse not blow when you plugged your cigarette lighter socket plug thing in (that you said had a 15amp fuse) - I'm surprised that the plastic melted before the fuse blew? (although the cig sockets are usually rated to only about 10amps so its a bit past that ....) Is there any chance that the cig lighter plug from your fridge has a wiring fault/short circuit in it - might be worth checking??

[Tracy&Andy]

Thank you so much for your advice.

Seems we have completely done it the wrong way (we inherited a small 2 way fridge with the van, that connected to the cigarette lighter socket, and just guessed we could do the same for the RM123. As they say, assume makes an ass of u and me!!!).

Neither of us are very good with electronics, so we'll take your advice, read the links and research it further. Sounds like a complicated job wiring relays to the battery! Might need to call in some expert help from some friends with more knowledge.

Thanks again,

Tracy and Andy

[Tracy&Andy]

The fridge has/requires two separate 12V supplies.

Thanks again for your information.

We have looked at the link, and now understand how the relay works, in theory!

You said there are 2 separate 12V supplies, but we can only find one set of wires (one brown, the other blue), which we took to be a positive and negative, which we wired (wrongly) into the cigarette lighter plug?!?

We will get help to wire the 15Amp relay from the battery, but cannot fathom the second supply to power the ignition so we can turn the fridge on with the gas supply (we would be happy to run it on gas while we are traveling). Where does this wire come from in the fridge. Are we just being dumb?

Sorry for our stupidity, but the wiring system is something we just haven't got our head around yet!

Thanks,

Tracy and Andy

[CJH]

Where does this wire come from in the fridge. Are we just being dumb?

Fig 11 in this manual seems to imply there's a terminal block on the underside of the fridge.

[Oldiebut goodie]

123, the terminals are on the back - there should be one 12v set for the igniter and separate one for the 12v element. (+230v one)
Put up a photo of the terminals on the back and we should be able to fathom them out for you.

[MidLifeCrisis]

You said there are 2 separate 12V supplies, but we can only find one set of wires (one brown, the other blue), which we took to be a positive and negative, which we wired (wrongly) into the cigarette lighter plug?!?

It does have an electronic ignitor, right?
Some of those fridges had a piezo ignitor that you just push with your finger.
There should be a switch (red?) on the front panel if you have the electronic ignitor?

[Tracy&Andy]

It does have an electronic ignitor, right?
Some of those fridges had a piezo ignitor that you just push with your finger.
There should be a switch (red?) on the front panel if you have the electronic ignitor?

Thanks everyone......

Yes it does have an electric ignition, not the piezo.

The wires we connected were from the back of the fridge, so that must be for the heating element.
The manual given to us by CJH does actually show the ignition terminal block on the underside, so we will need to check that (as there were no leads coming from it).

We will take some photos and upload them.

Really appreciate all of the help.

We will have cold!!!

[California Dreamin]

What you need is a dedicated split charge relay 'with' fridge take off......basically a relay that connects starter & leisure batteries together but only when the engine is running & also has a dedicated fridge feed...again, only supplying power with the engine running.
Exactly like this:

http://www.autoelectricsupplies.co.uk/product/824" onclick="window.open(this.href);return false;


One last 'FLY' in the ointment.....if this fridge was removed from a Westfalia camper van, then it will be jetted (the size of the jets allowing gas through to the burner) for a 50 millibar regulator, which is higher than we use here in the UK (28 millibar). The result will be a smaller flame from the lower gas pressure and possibly not enough heat for the thermocouple, which will result is frequent flame outs and/or, poor cooling performance.....you could just try it and see.

Martin

[Tracy&Andy]

Just a belated thank you to all the replies.

A friend of ours, with more knowledge of electronics than us, read and used all the advice everyone had posted, and together we followed the diagrams to work out how to wire in the fridge in with the relay.

Because of all your kind hope we had a perfectly working fridge, both 12V whilst driving, and working off the gas while parked, and we were able to enjoy a "chilled" weekend at Busfest, in Malvern.

Thanks again,

Tracy and Andy