Thetford Fridge 3-Way on Gas

wildebus

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Question for you 3-Way Fridge Gurus .....
I have a Thetford 3-way Fridge. Think it is a N175 with the internal freezer compartment. It is a model with the Auto Energy select feature.

It doesn't seem to want to always work on gas. Electric (12V and 240V) is fine, but the gas seems a touch unreliable. I sometimes go to the fridge and find it is no longer cold. I have gas in the bottle (right now it is virtually full) and the gas cooker starts no probs so gas is coming out the bottle and regulator.
I tried to start it yesterday and the auto ignition was doing its clicking thing for the 15 seconds and then timing out. I'd try again and same thing again.
When I took the vent off and watched what was happening I could see a spark going on; I could hear the gas coming out, so the basic actions seemed out but the burner just would not light?
This morning I tried again after coming back from driving the van and tried the fridge again and it worked straight away - burner lit on the first or second click.

Any ideas what this intermittant working might to due to? something needs cleaning? servicing? adjusting? I don't really 'do' gas so not familiar with the details of it.

Also, I watched a little youtube video on this kind of thing by someone with the same fridge this morning. it didn't really help, to be honest, but I did notice that he had a cover over the burner/thermocouple assembly part that he took off to show the burner, etc. I don't have any cover on mine? I am wondering if that might have been removed for servicing at some time and never refitted? would not having a cover cause the fridge not to work properly? maybe allow dirt in the area or mess with the airflow and be less efficient? I guess I should buy/make a cover plate to put back.
 
If it's a gas problem and you have not got much experience you should get some one out to fix it ..
 
So if its working now but not geting cold it could poss be the thermistor ...
 
So if its working now but not geting cold it could poss be the thermistor ...
No , it gets cold when it is running. It is just the burner not lighting always. This is why I suspect it is a simple adjustment thing and I don't want to be booking some bloke to come out to spend 30 seconds moving something and charging me 4 hours travel time plus a minimum call-out fee.

(in the same way as I would tell someone to do some basic checks such as 'is it plugged in' on their electrical device before booking a repair - and yes, I have had that and driven from Middlesex to Swansea (DVLC as was) to spend 30 seconds plugging in a cable when their printer didn't work - as they insisted everything was checked and insisted on a service visit)
 
We have a Thetford with separate freezer, can't remember model. If it hasn't been run on gas for more than a week it won't ignite. We have to turn it off and then on again in the hope it ignites, sometimes it takes three attempts. It's like there's no gas in the pipe.

I would like to do a pressure loss check to see if there's a leak.
 
I just had a look ... still running on gas and fridge cooler. turn the AC on and switched over to that. turned AC off and it switched back to gas but burner wouldn't light. needed 3 goes to light up and now on gas again. Really need it to switch sources reliabily!

Think a bit of a service is needed but can't call out anyone where I am as distances mean travel time costs are prohibitive
 
no, just changes the source to AC (the default) and the blue light flashes as there is no AC available
 
Try setting the temperature bars to half way when lighting. I find if it is on maximum it can cause occasional ignition problems. I also find it runs just as cool on half way or just above as it does on max.
 
Try setting the temperature bars to half way when lighting. I find if it is on maximum it can cause occasional ignition problems. I also find it runs just as cool on half way or just above as it does on max.
Interesting. Surprised it could have that effect, but I will try as you suggest (y)
 
does it come up as fault code 9 on the display?
I checked the manual and when the fridge is in Auto (SES) Mode, gas is selected and is not available, it tries AC and if that is not available you get an Error 11 - Energy Source not available.
I have set it now on non-Auto mode and gas and will see what happens in terms of error codes if it doesn't relight
 
sounds as if everything is working fine ,gas supply ,t/couple, jet ,flue etc . only thing i can think is the sparker needs adjusting . if it's too far away from the burner or dirty ,that could cause a weak spark .if was mine i would temp install another push button sparker and see if that sorted it
 
sounds as if everything is working fine ,gas supply ,t/couple, jet ,flue etc . only thing i can think is the sparker needs adjusting . if it's too far away from the burner or dirty ,that could cause a weak spark .if was mine i would temp install another push button sparker and see if that sorted it
Cheers. I am wondering if the little nozzles in the gas supply could be a bit sooted up and need a blowout? When I took the lower vent cover off, the base area was pretty clean and totally dry. lots of general dust as probably expected, but around the burner area there was what looked like black soot lying on the base. That could be have been many years accumulation of course.
Would a separate starter work with an electronically controlled fridge? would you use that in the 15 seconds the auto-starter was running to get the flame going so the fridge wouldn't "realise" it didn't start it itself?

Just been out to the Motorhome ... Fridge still running on the gas. Fridge not very cold but I think it takes an age to get down to temperature anyway. Put a temp sensor in on the cooling vanes and can monitor that on my system to see what is happening over time (been meaning to add one for a while and still have to route properly under the floor but ok for now).
 
i have no experience of modern fridges , just the old ones . i picked up a 3way last week ,a RM212. filthy burner and flue ,but once cleaned started cooling in about an hour .
i'm not sure your fridge's ''brain'' would care what lit it ,but it should recognise that it's lit . i'd light it with a lighter a few times and see what it does ,then maybe get a push button piezo
after cleaning of course
 
Maybe should keep one of those long-armed gas lighters handy to get it going if it doesn't want to light by itself and see if that works - I can't imagine putting a flame to gas would not start the burner!
(I much prefer the Compressor Fridges! Know where you are with those suckers :) )
 
I would try cleaning the burner out first before you try anything else. You say it hasn’t been cleaned for years, the manual for my Dometic fridge says the burner should be cleaned 2 or 3 times a year ( It’s a French reg van so the manufacturers assumption is that the van and fridge are used all year round, which they are) you say yours is well overdue. If the burner is even partly clogged, it could take a few goes to light ( or not light) and the fridge won’t cool properly.
If cleaning doesn’t fix it, then the jet could be partially blocked, and at this point, you would need to get it professionally sorted.
 
Well, it hasn't been cleaned since Sept last year, I know that. (no idea before that as before my ownership).
Thanks for advice (y)
 
Fridge on AC all night and temp went down to a steady recorded -1C, so it is cooling (actual temp not sure. I had to extend the sensor cable and that might have affected the reading slightly as temp based on voltage drop on cable. Also sensor direcyly on cooling vanes, not ambient (did that as that is how the fridge's own sensor is attached so can compare temp to power use (on AC anyway))).

i have no experience of modern fridges , just the old ones . i picked up a 3way last week ,a RM212. filthy burner and flue ,but once cleaned started cooling in about an hour .
i'm not sure your fridge's ''brain'' would care what lit it ,but it should recognise that it's lit . i'd light it with a lighter a few times and see what it does ,then maybe get a push button piezo
after cleaning of course
Turned off AC and fridge didn't start up as it switched to gas. @mr brown - the 'clicker' wasn't igniting the gas but used a lighter and instantly lit. Sounds like a gap issue? or spark a bit weak? (is a weak spark possible or is it more a matter of there/not there?)
 

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