Thetford Fridge 3-Way on Gas

If a burner clean out doesn’t work, it could be a blocked jet or faulty gas solenoid if you are getting a supply issue fault.
 
I would have thought if it has flat unvented sides, insulation would be fine? but it is not something which could be easily removed once in place, so have to think hard on this one I guess.
I would almost certainly add some 'programmable' forced venting at the rear with fans either blowing at the bottom or sucking at the top (or both!) - as the vents are there,may as well take advantage of them :)

The fact this is available in black makes a big difference. Silly I know, but if you are spending tens of thousands of pounds on a Motorhome, you don't want to cheapen it inadvertantly - and the white fridge could have looked like it was just shoved in the hole. The black one I think will look right. (the 12V option will have to be a pretty keen price now to retain my interest!)
 
Jenrai said:
I spoke to soon!! Just arrived back from a few days away running the fridge off gas. No problems until the last day when is started flashing with error code 11.
The manual says its a supply issue but I have 3/4 tank of LPG. It runs on battery, with the engine running and 230v on hook up but not gas.
So I am desperately ringing every place in Sussex I can find to get it fixed before next Thursday 😭 😭 😭 😭
I just dont have the confidence or skill to be poking around in the fridge workings.
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@Jenrai , Error Code 11 can be quite misleading.

In Auto mode, the fridge will use whatever source of energy is available, with gas being the last - and what you are using. What happens when Error 11 appears is that the fridge switched to gas, failed to ignite within 15 seconds and then switched to AC. You don't have AC available so error 11 came up - no energy source.
The problem is that once the fridge fails to start on gas, it will NEVER try to start on gas again until you turn it off fully and back on. using the push button to select gas again will not work until you have first turned the fridge off and on again.
I don't know how well that is known? I only know because I have read the Fridge Manual fully trying to get to grips with getting mine working.

So if you have not done so already, turn the fridge off (small rectangular button) - display goes off - , then turn it back on and see what happens. If if doesn't light and you want to try again on gas, turn the fridge off again and back on (this is essential when trying to restart after a failed gas attempt).
 
wildebus said:
I would have thought if it has flat unvented sides, insulation would be fine? but it is not something which could be easily removed once in place, so have to think hard on this one I guess.
I would almost certainly add some 'programmable' forced venting at the rear with fans either blowing at the bottom or sucking at the top (or both!) - as the vents are there,may as well take advantage of them :)

The fact this is available in black makes a big difference. Silly I know, but if you are spending tens of thousands of pounds on a Motorhome, you don't want to cheapen it inadvertantly - and the white fridge could have looked like it was just shoved in the hole. The black one I think will look right. (the 12V option will have to be a pretty keen price now to retain my interest!)
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I hope I'm not telling my grandmother how to suck eggs - but . .
If the fridge ditches heat via coils directly under the side skins then those sides need air circulation. Close fitting insulation will stop the fridge working.
If the dispersion is via the back skin then the chimney system in a motorhome home will be great and temperature controlled forced ventilation will be good in hot weather.

If it's side skinned and there is space (20-25mm) either side and above the fridge with good external vents it will work.
To be effective any forced ventilation will need to be well considered to get additional air flow in the right place.
 
@wildebus @Markd Thank you both for the advice and the support. Having phoned every place I could find everyone is booked, the end of August being the earliest. But I did have a lengthy conversation with a very knowledgable mobile techy. He said reseting the fridge a few times might clear the problem, he also mentioned that it might need a new pcb. At this point he warned me that getting hold of a pcb could be a problem as he says there is a supply shortage. No problem, as I know a local dealer that has all sorts of stuff. So after a short round trip and £165 later I am now the proud owner of a new pcb, just no one to fit it.

Going to open her up tomorrow and see what I find o_O

I'll update you after a rummage around.
 
Markd said:
I hope I'm not telling my grandmother how to suck eggs - but . .
If the fridge ditches heat via coils directly under the side skins then those sides need air circulation. Close fitting insulation will stop the fridge working.
If the dispersion is via the back skin then the chimney system in a motorhome home will be great and temperature controlled forced ventilation will be good in hot weather.

If it's side skinned and there is space (20-25mm) either side and above the fridge with good external vents it will work.
To be effective any forced ventilation will need to be well considered to get additional air flow in the right place.
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I would think logically that because fridges tend to be fitted closely to cabinets either side, the ventilation would generally be arranged around the back - and the sides woulds generally have insulation on the sides between the outer panel and the fridge inside.

But I am just picturing and imagining what I think would make sense :)
 
I agree - they 'always' used to have an exposed condenser on the back this worked well as there was a good chimney effect and keeping the hot 'radiator' away from the cold box meant reduced insulation thickness.
And you could fit them snugly into units.
Then for some reason everything had to be smooth as the proverbial with no tatty bits to catch dust or provide space for things to fall down the back.
The condenser tubes are right under the skin and because of that insulation thicknesses increased markedly - maybe you can remember the change and how much smaller inside freezers in particular became?
Now you have to leave at least 25mm at the sides for the heat to dissipate into the new side chimneys.

The sides of my aforementioned domestic fridge freezer are quite hot to the touch today with high 20s inside house temperature.

I'm sure the LEC you're considering will work but I think that you'll find that it is side skin cooled.
I've looked at the installation instructions and side-top ventilation is required and if it's narrower than the space you have available it'll be fine.
You may find when you get it that it rear cooled in which case you can increase the insulation.
You might even find a retailer customer service - technical team that can tell you before you buy but I won't be holding my breath 😀
 
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Jenrai said:
@wildebus @Markd Thank you both for the advice and the support. Having phoned every place I could find everyone is booked, the end of August being the earliest. But I did have a lengthy conversation with a very knowledgable mobile techy. He said reseting the fridge a few times might clear the problem, he also mentioned that it might need a new pcb. At this point he warned me that getting hold of a pcb could be a problem as he says there is a supply shortage. No problem, as I know a local dealer that has all sorts of stuff. So after a short round trip and £165 later I am now the proud owner of a new pcb, just no one to fit it.

Going to open her up tomorrow and see what I find o_O

I'll update you after a rummage around.
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It's up to you of course but it'll only take a few minutes to reset the 'computer' as suggested by Wildebus - if after doing that it does try to light the gas but fails you can quickly clean up the burner and air inlet holes.
Technically if the jet has to be disconnected to be cleaned it should be done by a competent person so if you have any doubts - don't!
I expect the PCB is at the bottom rear so the same access cover will have to be removed to clean the burner as change pcb.
I've a sneaking suspicion that you've just acquired a spare pcb that should guarantee full functionality for the rest of time 😀
 
I've seen quite a few comments on forums saying "you'll need a new PCB" for just about any fault someone might say they have (including the suggestion to me for my non gas-lighting).
I'm dubious. You can generally see if something is 'electronical' in its problem or something is more fundementally basic. for example, my problem was not lighting - a new PCB was suggested.
I moved the igniter rod (I am sure it has a proper name, but that will do) fractionally closer to the burner, after which it NEVER failed to light when it was meant to. When trouble-shooting, I could hear the gas; I could hear the clicking from the ignitor thingy; I could see the sparks - and if I put a flame to the burner it lit. The electronics could not possibly be needing to do anything more - it really couldn't be anything then the gas not being lit (I have a gas soldering iron and I use a flame on that as the flint is a pain to use - same thing here in many ways).

I would not unpack the new PCB yet as you may be able to send it back!
 
The 'igniter rod' may also has a secondary function as flame failure device?
After the high voltage sparks have lit the flame a low voltage is applied to the probe and because the flame causes ionization a very low current flows from the probe to earth and this could tell the pcb to hold the gas solenoid open.
So a dual function rather than having a separate good old fashioned capillary bulb holding the valve open mechanically.
Or do modern fridges use a thermocouple?

I had problems with my flame detection not turning the spark off. Fortunately my fridge-freezer is old enough to have a capillary requiring manual depression of the valve at initial ignition - so the burner carried on.
I eventually tracked the problem down to high resistance in the manual mode selection switch blades - cured by cleaning and tightening. Which sounds easy but did require fridge removal to access the top mounted rotary switch 😡
Probably took years off the ignite circuit life though 😀
Again pcb issues had been suggested by remote 'diagnosis'
 
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As you can see from the above pictures the gas part seems clear of any soot/rust and the metal rod is right in the flames when it lights. The repeated problem I have is it will light for around 20 seconds then go out and flash error code 11.

So it looks like a pcb replacement as you can see in the second picture there is no way I am unplugging that lot.

The issue I have is no one can do the work, tried every motorhome related techie but they are all busy. I was wondering could a general electrician do the work or a fridge techie? I don't know your suggestions would be appreciated :)
 
The burner looks clean enough.
And the electrode is too.
Do you see any obvious issues on pcb?
It's a flat view but there a pair of solder joints in the middle that look different to the rest?
 
So if it lights the problem is with flame detection.
If there is no other sensor in the flame then the ignition probe is dual function.
If you take it out you can lightly clean it up with fine sandpaper and try again.
You may need to adjust position in flame slightly to ensure low current flow through the flame.
Be gentle with it as you don't want to crack the ceramic insulator and allow high voltage track to earth.
A few minutes more fiddling before you need the pcb out.
Can you see any obvious issues on the board or differences to your replacement? Assuming you can check without taking it out of sealed bag?
 
You're daunted by the prospect of changing the pcb but you've done most of the leg work.
The cover is off and you've got a record of which plug-wire goes where.
I suspect that all you would need to do now is take out the two self tapping screws through the board and it would come loose.
 
@Jenrai
Here's a video showing a solution to your very problem.
A great pity that the bloke didn't have a torch handy or make the effort to get one though!

 
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I've not got much extra to offer (and your burner going off after 20 seconds does sounds like thermocouple not detecting heat, so cutting gas for safety)

But good on you for having a go with this in a safe way. Approach things in a logical way and you will often find the solution :)

In terms of looking for someone to do some swapping of parts and you can't get hold of a "fridge engineer", I would have though the type of person would be someone who used to fix TVs and Radio, or maybe Computers - they are all of a muchness really and involve disconnection and reconnection of parts.
 
Markd said:
You're daunted by the prospect of changing the pcb but you've done most of the leg work.
The cover is off and you've got a record of which plug-wire goes where.
I suspect that all you would need to do now is take out the two self tapping screws through the board and it would come loose.
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I think the entire assembly is removed and the plugs swaped over, rather than just the actual Printed Circuit Board itself?

For example, see this image showing a replacement power board for a Thetford Fridge - https://www.jacksonsleisure.com/car...hetford/fridges/sr/powerboard/control/module/
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looks like a unclip old, reclip new to swap over?
 
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