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geoffh

Sep 20, 2006
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We bought a new lunar quasar 462 in september 2006

Main outstanding problem is the fridge will not always work on 12volt there appears to be some sort of outstanding design problem with the theford fridge and the electrics on the van.

So if you are buying a new van with this fridge check before your leave dealer

I Collected my van after it was in for some repairs and the fridge didn't work on collection Like a fool I took it away with the reason that untill the battery is fully charged it won't.

Well when i bought the van nobody said the van would not work like that so i think it is time to take it back
 
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WatsonJohnG

Mar 14, 2005
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Hi geoff

Its just occurred to me that some Thetford and Dometic fridges now work via the thermostat when on 12V.

Have you tried turning the thermostat up

Just a thought
 
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bertie1

Dec 10, 2006
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Not sure what you are saying, Geoff. Our new 2006 van has a Thetford fridge. This is designed to operate on 240 volt mains or gas. The 12 volt operation is for keeping the temperature down during towing, and power is supplied through the 12S socket on the car.

If it were to be connected to run at 12 volts on site, it would soon flatten your leisure battery.
 
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Geoff,

I agree with the comments made that your post is not clear on what actually is the problem. You state the fridge didn't work after colecting it after some repairs had been done. Does that mean it worked before that point?

It is unlikely that the van has a fault, unless someone somewhere threw a wobbler during the fit out. The most common issue with fridges and 12 volt is in the car side of things with wiring that is not beefy enough to take the load. I also assume you have 2 7 pin sockets, not a 13 pin one as here again sometimes the wiring can get confused. Also there is a relay in the circuit that prevents power reaching the fridge until the car revs are sufficient to cope with the power drain.

From personal experience I would suggest that Thetford fridges seem to be more efficient than equivalent Dometic ones, but others may disagree. One downside of Thetford tho' is that there is no light to tell you everything is working, as with Dometic.
 
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bertie1

Dec 10, 2006
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Geoff,

I agree with the comments made that your post is not clear on what actually is the problem. You state the fridge didn't work after colecting it after some repairs had been done. Does that mean it worked before that point?

It is unlikely that the van has a fault, unless someone somewhere threw a wobbler during the fit out. The most common issue with fridges and 12 volt is in the car side of things with wiring that is not beefy enough to take the load. I also assume you have 2 7 pin sockets, not a 13 pin one as here again sometimes the wiring can get confused. Also there is a relay in the circuit that prevents power reaching the fridge until the car revs are sufficient to cope with the power drain.

From personal experience I would suggest that Thetford fridges seem to be more efficient than equivalent Dometic ones, but others may disagree. One downside of Thetford tho' is that there is no light to tell you everything is working, as with Dometic.
Click to expand...
My Thetford fridge has a blue light in the panel, which flashes if the fridge isn't working.
 
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MikeP

Mar 14, 2005
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Connect an ammeter in-line. If the car is producing about 13.5v with the engine at about 2000 rpm and the wiring is beefy enough, then the fridge should be drawing current. If not, go back to the dealer. If there is no output at the car, that's your problem. It would be wise to connect someone else's car to your caravan to see if it works.

How old is your car? If it isn't recent, then you might need to connect pin 7 (centre) to earth with 2.5mm cable. From memory, I think the new wiring came in around 1999 or 2000. Cars wired for towing before 1999 are probably wired the old way.
 
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WatsonJohnG

Mar 14, 2005
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Exactly the point I was making under "12s centre pin" earlier under that thread further down the "Technical" postings.

Its more likely to be a car related problem or the thermostat on the fridge is set to "off"
 
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WatsonJohnG

Mar 14, 2005
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Thats very interesting Geoff.

Its hard to understand why Thetford would require a 12V source from the van battery for the fridge to work on 12V off the car when the habitation relay in post 1996ish vans switches the van leisure battery off on tow.

If that is the case it means that manufacturers must wire vans differently for the Thetford fridge which can't be a popular move.

As you said in a previous posting its not progress.

When you went to Spain and had problems on 12V was that when the centre pin burnt out?

I would still have doubts about the car relay especially if its voltage sensing as I have seen a few on rallies that have played up.

When I put one on my car the fridge was still on half an hour after switching off the engine.I have reverted to the mechanical relay with a seperate 12V trigger.

Best of luck
 
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geoffh

Sep 20, 2006
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at last you can understand me it is not your fault John it is just a problem I have trying to explain things clearly

the dealer changed the plug on my return from spain

Will report back later
 
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WatsonJohnG

Mar 14, 2005
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Hi again Geoff.

I am grateful to you for raising this issue which was news to me.

I took the van in for service yesterday and asked about the 12V from the leisure battery to the fridge on the Thetford fridge and was told that the same applies on the Dometic fridges and has for 2 years.

I then read the Bailey manual but saw nothing to clarify the situation.

The Dometic manual under 12V faults and also in fitting instructions says as you were told that 12V from the leisure battery to the fridge control panel must be maintained.

So there we have it its needed for the controls to work and the main load still comes via the 12S plug for cooling but it needs the say so from the controls via the 12V leisure battery.

It may then follow that you could have a duff 12V leisure battery.

Most interesting and thanks again
 
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geoffh

Sep 20, 2006
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Hi John

Funny enough it is going in monday morning along with a letter asking them to fix it or refund my money.

I spoke to thetfords technical people last week and if i have explained it correctly it also appears that the fridge venting system must be sealed so that no gases can enter the caravan Well i can see daylight from inside one of the draws

The saga goes on
 
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WatsonJohnG

Mar 14, 2005
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Geoff hope you get it sorted.

Its the gas exhaust vent that has to be sealed from the inside so you may be OK if its just the hot air vent that you can see through
 
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WatsonJohnG

Mar 14, 2005
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Came across this on the Dometic website when lookin for something else!!!

Caravan owners

Please be aware that the AES and MES versions require a continuous 12V supply.
 
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geoffh

Sep 20, 2006
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John

Could you tell me where the gas exhaust vent is and what it would look like ?

I have only two vents on the side of my van and a large gap behind the fridge I just thought the gas exhaust and fridge hot air both went into the same.
 
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Royston

Mar 14, 2005
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Hi Geoff,

I too think the thetford fridge controls are not a patch on the domestic fridges.

With the domestic fridge green light switch for 230 volts and the red light switch for 12 volt supply,never had any problem with keeping the fridge cold.

I have only done two trips with my series 5 Ranger only to local sites hopeing that the 12 volt supply works when we head for Scotland in May.

Royston
 
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geoffh

Sep 20, 2006
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Hi Royston

I have spoken to Lunar sales department and he said we do seem to get the odd fridge in a batch with a fault and they are trying to resolve this with the supplier

No comment I will wait and see and then update

Thanks all
 
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WatsonJohnG

Mar 14, 2005
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Royston I couldn't agree more

The model of Dometic fridge you speak of was great.

You just left both red and green switches on as you wanted the red 12V on when on tow and it only worked anyway on the car AND you could see that it was working because the red light was on.

You could leave the 230V on as well as you wanted it on onsite and when you unplugged it went off.You just had to remember to switch off when in storage but the green light reminded you to do that anyway.

The Dometic and Thetford brought out fridges with NO warning lights and I fitted my own followed by a few for friends!!!

Now they have warning lights again BUT you have to remember to turn a rotary switch every time.

Its not progress---well not in the right direction!!
 
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geoffh

Sep 20, 2006
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update

My dealer has confirmed what John and I have spoken about is that the fridge control panel needs a fully charged caravan to tell the fridge to accept the 12volt from the car to make it cool down

(talk about making hard work) well now they have decided to add an extra relay so that when I connect up it will not need to see a fully charged battery before it will work.They are going keep it this week and run tests before I collect it.

I hope this is the end of this saga and I will have a caravan which I bought to go touring with without the need for a coolbox.

Sorry to go on but it has taken too long time to get the dealer to rectify this fault.
 
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WatsonJohnG

Mar 14, 2005
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Geoff its been most interesting and I have learnt something that I didn't know before.

Maybe the problem you have is voltage drop through cable that is too thin and the relay may be to use the existing wire to switch a heavier cable thus giving a higher voltage at the fridge.

I had a problem with the TV in the Senator that was cured by upping the cable size but then that would use more than the electronics to the fridge.

Lets hope it works and keep us posted
 
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geoffh

Sep 20, 2006
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At long last I now I have a Fridge which works on 12 volt every time you plug it in(well I hope so)

I have had the relay in the car changed

The caravan has had the wiring modified it now no longer needs a fully charged battery before it will cool just enough volts to make the control panel operate.

One of the main reason of all these problems is with large cooling element on the thetford fridge and the new wiring standards.

Sorry to go on but if anybody needs any info please get in touch and maybe you won't suffer the stress I have.
 
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