Fridge problem

[Figaro]

I've a Dometic 3 way fridge RM6401L and it's been working well on all three power sources until this week when it's stopped cooling on gas.
12 and 230 volts are fine.
The fridge lights on gas and stays lit and the fridge fans come on periodically as I'd expect, so somethings getting hot, but no cooling.

The only thing I can think of is some debris has fallen down the flue, but no idea if that would cause these symptoms ?
Unfortunately the lower vent is mounted in the floor and inaccessible behind the bumper. So I can't get to it to clean without taking the fridge out.
I'm on the road in Italy heading for south France and so not really possible.

I'd read an excellent write up on here by I think autorouter ? explaining how the fridge works on all sources, I thought I'd bookmarked it for future reference, but can I find it ? no.

Anyone have any ideas for a simple fix

TIA

 

[Jimbohorlicks]

Can you get a vacuum cleaner hose ,or a thinner tube attached down by the burner to suck out any debris ?

 

[Figaro]

Can you get a vacuum cleaner hose ,or a thinner tube attached down by the burner to suck out any debris ?

Tried that and it made no difference
Tricky to do as there is some kind of baffle in the flue so I don't know how effective that would ever be.
I believe when debris gathers or falls it usually stops the fridge lighting ?
Mine lights and stays lit

It's cramping my FLT credentials at the moment

 

[monzer]

Tricky if you can't get in to the bottom vent but does sound the same as my problem....

Not another fridge not working on gas thread

Sorry did I say it wasn't another fridge not working on gas thread? Damn auto correct ;) Electrolux 3 way fridge. It's been working fine on gas at home even in nice warm-ish weather. Haven't been on hook up for a while but pretty sure it was fine. Been away now and it's been on and off a few...

www.motorhomefun.co.uk

Certainly sounds like the flue needs cleaned out.

 

[Figaro]

Tricky if you can't get in to the bottom vent but does sound the same as my problem....

Not another fridge not working on gas thread

Sorry did I say it wasn't another fridge not working on gas thread? Damn auto correct ;) Electrolux 3 way fridge. It's been working fine on gas at home even in nice warm-ish weather. Haven't been on hook up for a while but pretty sure it was fine. Been away now and it's been on and off a few...

www.motorhomefun.co.uk

Certainly sounds like the flue needs cleaned out.

Yes it does

No access to the lower vent is a real pita

It'll have to wait until I'm home and can get the fridge out

Thanks

^{_{Subscribers  do not see these advertisements}}

 

[paddymcc]

In mine the baffle is suspended in the flue on a thin wire that attaches to the top of the flue.You should be able to unclip it an lift it out in order to pass a thin tube down attached to the end of the vacuum hose

 

[Figaro]

Ok, so back home now and investigation underway into why fridge stopped working on gas.
I've taken fridge out, no debris apparent at gas jet, baffle removed and bottle brush pushed down the flue. Some debris fell out but not that much really.
All vacuumed up and general clean up of back of fridge.

Is there anything else I need to check whilst it's out ?

I could replace the gas jet I suppose but it was lighting ok, just wouldn't cool.
From what I can see, all 3 sources use the same refridgerant / gas circuit which goes behind the aluminum cowl encasing the flue, I assume this is where it heats the refridgerant gas in the pipework.
If anyone can confirm this that would be helpful as it would exclude a problem with the refridgerant.
Unfortunately I can't reconnect and test it while it's out and have no lower vent to check things through.
TIA

 

[68c]

Yes, there are the three heat sources inside that tube, any of which will make the fridge cool. Can you see if the gas flame is actualy alight? If not could be an ignition fault, test by holding one of those gas lighters at the bottom of thr exhaust tube. If it does not light then there is no gas flow. There is a small filter before the gas jet, a sort of sintered metal affair, that gums ups particularly in cold weather. Clean in a solvent, lighter fluid etc.

 

[Figaro]

Thanks, I'll check that filter tomorrow.
Unfortunately it's impossible to see the flame when the fridge is installed with no lower vent or inspection window inside the fridge as some models have.
I assume it lit as the flashing igniter light went out.
I might see if I can rig up a temporary gas supply with plastic tube

 

[Bessy765]

Have you check that the regulator is providing enough gas. A lot of Truma reg have failed due to contamination

^{_{Subscribers  do not see these advertisements}}

 

[68c]

Thanks, I'll check that filter tomorrow.
Unfortunately it's impossible to see the flame when the fridge is installed with no lower vent or inspection window inside the fridge as some models have.
I assume it lit as the flashing igniter light went out.
I might see if I can rig up a temporary gas supply with plastic

Assuming both the 12v and 240v heaters are cold, feel if any heat comes from the exhaust when trying on gas, it will not be very hot but should be noticeable.
One fault I had after a rather bumpy ride was the gas had lit up OK and felt warm at the exhaust but little cooling. Turned out the jolting had dislodged the baffle inside the exhaust tube, the baffle is about three inches long and hangs loose on a wire inside the exhaust tube. It is twisted to encourage the heat from the flame to spiral (helix?) and stay in contact with the exhaust tube inner surface and so heat the cooling chemicals. For info the gas exhaust pipe is the inner tube, about one inch in diameter. This wrapped in something like fibreglass wool which is then covered with the shiny three inch sleeve. The chemical tube runs up inside this insulated tube in contact with the heated exhaust tube. The two electric elements are long rods with wires attached also inside the insulation and in contact with the chemical tube. You are correct in assuming there is no major problem with the fluid side of things if it cools on electric.

 

[Figaro]

Have you check that the regulator is providing enough gas. A lot of Truma reg have failed due to contamination

Is that the regulator at the gas bottles or is there one on the fridge as well ?
Boiler and hob work ok.

 

[Figaro]

Assuming both the 12v and 240v heaters are cold, feel if any heat comes from the exhaust when trying on gas, it will not be very hot but should be noticeable.
One fault I had after a rather bumpy ride was the gas had lit up OK and felt warm at the exhaust but little cooling. Turned out the jolting had dislodged the baffle inside the exhaust tube, the baffle is about three inches long and hangs loose on a wire inside the exhaust tube. It is twisted to encourage the heat from the flame to spiral (helix?) and stay in contact with the exhaust tube inner surface and so heat the cooling chemicals. For info the gas exhaust pipe is the inner tube, about one inch in diameter. This wrapped in something like fibreglass wool which is then covered with the shiny three inch sleeve. The chemical tube runs up inside this insulated tube in contact with the heated exhaust tube. The two electric elements are long rods with wires attached also inside the insulation and in contact with the chemical tube. You are correct in assuming there is no major problem with the fluid side of things if it cools on electric.

The baffle looked to be copper but the wire is steel and badly corroded. I'll strip a length of twin & earth I think for the copper wire and make a replacement.

 

[Reallyretired]

Is the gas jet operating at full blast. Sometimes a partial blockage may let it light but not produce enough heat. Should be an audible roaring sound though you may have trouble hearing it as your bottom vent is inaccessible.

 

[Figaro]

How 'large' should the flame be ?
I can't say I've ever heard it roaring but as you say with no lower vent it's perhaps not suprising
I'll see if I can rig up a temporary gas supply tomorrow without electrics connected and see what the flame is like

^{_{Subscribers  do not see these advertisements}}

 

[68c]

I have never heard the flame roar. The flame should be blue and about 3/4" long. Of course in you installation you cannot see it. I do not remèmber the exhaust baffle being copper. I suppose a length of copper wire to hang it would be OK to test but would probably get the real part in the due course of time.

 

[Bessy765]

Anything like this? Turn sound up first short clip!

 

[Figaro]

Thats quite a roar !

 

[Bessy765]

I did wonder if my regulator is letting too much gas in I have posted a separate post so not to hijack this one!

 

[jezport]

Is the gas jet operating at full blast. Sometimes a partial blockage may let it light but not produce enough heat. Should be an audible roaring sound though you may have trouble hearing it as your bottom vent is inaccessible.

This is what mine was like, burning but not roaring until I cleaned the jet

^{_{Subscribers  do not see these advertisements}}

 

[denisejoe]

The easiest way to check if gas is lit is to feel on the right side of the top vent to see if you can feel any warmth.
ps saw a German with the same van as you and he had installed a what looked cassette door where the gas burner goes.

 

[mitzimad]

clean the jet is the answer 99 times out of a hundred

 

[Figaro]

An update : Gas jet assembly removed and flue cleaned out. Neither were particularly dirty.
I blew some compressed air and vacced the gas jet aware not to poke anything in it.
Reassembled and all working nicely.
I can only assume it was lighting but the flame was restricted by debris preventing any cooling effect.
I also took the opportunity to extend the electrical cables to make removal easier in the future. Previously I had to lift the gas hob in order to disconnect them, and skin my knuckles in the process.
I couldn't find a filter to clean on the gas line though.
Hopefully it won't need any more attention for a while

 

[pappajohn]

If it's lit you should feel heat at the top vent, the flue is usually to one end of the vent grid.
Run your hand along the vent feeling for warm air.
It could also be the conductive paste behind the inner cooling fins. Unlikely if it's working properly on other sources though.

 

[Figaro]

If it's lit you should feel heat at the top vent, the flue is usually to one end of the vent grid.
Run your hand along the vent feeling for warm air.
It could also be the conductive paste behind the inner cooling fins. Unlikely if it's working properly on other sources though.

When it was running on gas but not cooling, it did seem to be warm at the vent, but as said, no cooling
All seems to be working ok now though, so not sure what the problem was, I can only assume lit but not fully for some reason.
I replaced the thermal paste a couple of years ago and found a big improvement

^{_{Subscribers  do not see these advertisements}}

 

[JJ]

I had the exact same problem which was fixed yesterday by fitting a new burner/jet and a new gas control valve.

(Completely stripping down and cleaning the burner and flue hadn't helped.)

I am now also free to go "off site" motorhoming once again... yipppppy!

JJ