Thetford Fridge 3-Way on Gas

wildebus said:
Burner out and gave the flue a good old tapping with the end of a screwdriver ....
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Not a massive amount of soot really I think (maybe it is though?) but certainly wouldn't really want that dropping into the burner assembly.

The Fridge is starting instantly on gas, which was the original issue I was wanting to resolve, so that is sorted which is great. A little photo of the burner as it is running now (before I put the covers back though of course)
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It looks pretty good to me?

There is an little caveat to this now ... There are 5 slots in the burner and in the photos and videos of the burners on line they are all open.
However I had some inserts in the burner which must act as some kind of restrictor?
The first photo shows the burner as I took it out. The second photo shows the plates removed (they are loose and just drop into the slots)
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I took them out to give the burner a bit of a blow-out with a compressor (nothing came out) and decided at this stage to leave them out (kept though in case need to go back) and reassembled the complete burner area assembly

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Have to see how it goes now. The Fridge is 17C right now. Let's see what happens! 🤞
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Now that's a use for a broken jigsaw blade I've never seen before ;)
 
I read that the freezer section is cooled first and only when that gets down does anything really happen in the fridge and they do say 12 hours or so - but you've given it much longer.
It is beginning to look as if you do have a restriction in the coolant circuit if it doesn't perform any better overnight.
Which as you say might be cured by turning the fridge over - not that easy in the van!
 
Markd said:
I read that the freezer section is cooled first and only when that gets down does anything really happen in the fridge and they do say 12 hours or so - but you've given it much longer.
It is beginning to look as if you do have a restriction in the coolant circuit if it doesn't perform any better overnight.
Which as you say might be cured by turning the fridge over - not that easy in the van!
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Plan is to invert it tomorrow (the fridge, not the van :) )

All electrical connections removed (y)
Gas pipe disconnected (y)
Fixing screws removed (y)

Rock and Roll :cool:
 
Webby said:
The auto selector can cause problems. I think there is a delay so that if you are on battery and pull in for fuel the gas does not spark up as soon as you switch the engine off.
We always use manual selection......................even then when changing source to gas we have to leave it switched off for a while.I guess the delay function still kicks in.
As said keep the burner area clean, but also we find it sometimes needs a rap on gas regulator or solenoid which can stick and stop the gas coming through when required.......trace the gas pipe back from the burner
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Hi, Yes we got the Thetford N150 -N175 3 way fridge with inside freezer and have had same problem on 2 separate occasions o ce 3 years ago ans same problem 2 months ago, worked fine on electric but not Gas. Just kept " clicking trying to ignite but would ignite for 20 secs then cuts out, ( on this last occasion , 3 years ago no ignition ) The Fault is the spark electrode probe. It's just a thin metal probe with ceramic sleeve near end and two wires for power at other end. Got the new replacement online from Jacksons liesure on the wirral for aprox £16.00 from memory. Got a qualified electrician friend I know to fit it. Not a big job or costly. After both times problem solved, does work fine but after last replacement took several attempts over 2 days to get a successful ignition just keep trying , works great now. Hope that helps.
 
@wildebus
At the price and hassle of any replacement inversion is work a try.
Whilst it's out and upside down you'll be able to double check that the chimney is clean.
You'll also be able to check operation on electricity and measure temperatures at various pint in the refrigeration circuit - I expect you e done some internet research on what to look for?
I hope you get it going again - or prove that it's past redemption.

In the spirit of enquiry and comparison I put mine in ehu today (nothing inside) and while the freezer is getting cold the fridge isn't frosting up.
I don't have thermometers available so can't give definitive numbers but I'm a bit disappointed after 12 hours - ambient was 25⁰ this afternoon and fridge on sunny side.
 
Documentation Time!
I don't rely on my memory when it comes to connections, so a photograph is handy as a check to what wire is what, especially when cable colours are pretty random!
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(Added labels to all the Thetford cables once disconnected just to make sure :) )
 
New fridge in :) it is a decent size at 94L but I would like a proper freezer compartment rather than an ice-box :unsure:

But the difference in performance over a 3-Way - even a fully working 3-way - is tremendous. The fridge has been plugged in for just 30 minutes ...
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(that spike on the AC Output Power is the system just managing to capture the in-rush on compressor startup - lasts 2 seconds)

And the load is so low (even taking inverter into account), the MPPT controller hasn't even been kicked out of float mode!
1626353169155.png
 
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Markd said:
@wildebus
At the price and hassle of any replacement inversion is work a try.
Whilst it's out and upside down you'll be able to double check that the chimney is clean.
You'll also be able to check operation on electricity and measure temperatures at various pint in the refrigeration circuit - I expect you e done some internet research on what to look for?
I hope you get it going again - or prove that it's past redemption.

In the spirit of enquiry and comparison I put mine in ehu today (nothing inside) and while the freezer is getting cold the fridge isn't frosting up.
I don't have thermometers available so can't give definitive numbers but I'm a bit disappointed after 12 hours - ambient was 25⁰ this afternoon and fridge on sunny side.
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Comparing the Fridge temp relative to the Ambient ... And bearing in mind the new fridge is both a little further away from the vent (still on the sunny side and it is certainly sunny today!) and is not sealed front to rear, this is my data for the last 6 hours.
You see the classic duty-cycle on the compressor once the fridge has settled down (bearing in mind the switching on at 13:00 is the first time it has been switched on since shipped from the factory).
Looking at this reminded me why I got a compressor fridge in the Campervan rather than an Absorption.
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The duty cycle currently is around 60:40 on/off which is a bit higher then typical but I think this will be due to the relatively warm ambient temp. It will be interesting to see how/if it changes during the night.
 
Very impressive performance from the 'little' fridge.
If I remember correctly your battery bank is 100Ah lithium plus 300Ah lead but I don't recall the solar capacity.
Maybe you could stack it with a small freezer so you have flexibility to use dedicated freezer only on longer trips?
Or is it a bit narrow for the space available?
 
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Markd said:
Very impressive performance from the 'little' fridge.
If I remember correctly your battery bank is 100Ah lithium plus 300Ah lead but 8 don't recall the solar capacity.
Maybe you could stack it with a small freezer so you have flexibility to use dedicated freezer only on longer trips?
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I have thought about that actually :) but location is a problem and not quite got a space large enough and don't like loose things (something I like about my motorhome is the 'tidyiness' of it) I was going to get another "motorhome" fridge but of the 12V compressor variety - but I am thinking a 240V one would be just as effective, with a saving of upto £1,000, which is pretty significant!
I've put the two icepops I had just laying in the Thetford into the new fridge and they are nicely frozen.

Ref Solar - Got 270W on the roof, backed up by 100W portable kit for extra harvesting or if the van is in shade (used it today for that very reason :) )

Identifed what would be a good 240V Fridge/Freezer for about £250 but I am actually tempted to stick with what was going to be a temporary measure - identical model in the camper for over 3 years and never missed a beat so a great track record there.
Not a bad size and it would not be that hard to make a tidy frame to box it in and also have a shelf in the gap (which would actually be a great location for the Microwave as it happens). I think this fridge is in fact a similar size to many motorhome fridges anyway?
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We have the same intermittent problem! I take the cover off the burner assembly and clean the thermocouple with the flat blade of a screwdriver, and works for another 6 weeks ish. And also ours sometimes works after a drive around!!!
Let me know if you want me to take a picture and send it (of the thermocouple)?
 
The existing high level vent would be handy for dumping the waste heat from a microwave.
A d if all built in would look neat and tidy.
We like having a freezer compartment for food we use a little of quite often.

Thx for update on power supply - obviously a microwave is well within your off grid capacity.
 
Markd said:
The existing high level vent would be handy for dumping the waste heat from a microwave.
A d if all built in would look neat and tidy.
We like having a freezer compartment for food we use a little of quite often.

Thx for update on power supply - obviously a microwave is well within your off grid capacity.
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@Markd , you mentioned you don't have a way to check the temp currently? Have a look at this device - https://amzn.to/3iiqyL0 .
Currently got a voucher for £3 off so is £11 today and logs the temp constantly, saves 20 days of history which looks like you can display on your phone? Sounds like a great device to check how a fridge is performing at a very reasonable price?
I've ordered one to look at the freezer compartment and also can use on the Thetford once that is the right way up and start checking it out.

PS. The Microwave is handy. Used it for 5 minutes to part-cook a baked potato. Took 1% out the battery. Happy enough with that :)
 
Markd said:
Thx for suggestion - I wasn't sure about temp range but it is good for -20⁰C apparently.
I also looked at this
It doesn't track - but is geared to sub zero temps with lithium batteries.

I'll probably stick with 'is the beer cold' as my guide 😀 but it's amazing what is available nowadays.
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I have those. One sensor in the fridge, one in the freezer and the display is above the hab door. They seem pretty accurate and have been running for over 2 years on the same lithium batteries.
 
I saw those ones and they look good as well (y)
I liked the idea of being able to see the changes and not just the Min and Max values when seeing how something is working, so the one which appears to do that with a 20 day store and bluetooth connection to an phone app - plus an app as well - and all for £11 seems too good to be true so had to give it a whirl :D (arriving tomorrow).
Got 4 sensors connected to the Victeon Cerbo - Battery, Room, Electrics Compartment (so can check if inverter or charger getting a bit warm), and Fridge. Be nice to have a 5th one for the Freezer connected but Cerbo only has 4 ports :(.
 
Markd said:
Very impressive performance from the 'little' fridge.
If I remember correctly your battery bank is 100Ah lithium plus 300Ah lead but I don't recall the solar capacity.
Maybe you could stack it with a small freezer so you have flexibility to use dedicated freezer only on longer trips?
Or is it a bit narrow for the space available?
Click to expand...

Bit of Comparison between night and day ...
Early this morning:
Duty Cycle around 19 minutes - Fridge goes on for 5 minutes and then off for 13 minutes. When on it draws 34W
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12 Hours earlier:
Duty Cycle is still around 19 minutes and the power when on is still 34W, but here the On time is 11 minutes and the Off time is 8 minutes.
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When I plotted the 3-Way Fridge, once it got down to the set temp, it did also have a duty cycle, but was typically around 75% on, 25% off, and the power when on was around 210W.
It really is not feasible to run a 3-way on battery power for any significant length of time overnight, but good solar harvesting could give you a decent few hours during the day.
 
I think the main point about 3 way is to run on gas when stationary.
When on mains there is a genuine thermostat which you can hear click in-out if you turn the temperature control - but 75% @ 200W is quite a lot of power.
As you've said before compressors are 5-7 times as efficient and your figures today prove that again.
The manufacturers also talk about temperature control on gas but on the old capillary systems this can't be much more than a bit of flow regulation rather than turn on and off.
This is sensible a way for an operating system that takes so long to get going and can establish a balanced system and can often be set for reasonably low consumption.
Do the more modern electric controls have a solenoid and cycle on-off?

Anyway- with a couple of hundred watts of solar and 400Ah of storage a house sized compressor fridge-freezer is a viable option off grid even when parked up for a few days.
In weather like we've currently got the sun probably delivers more power that it takes in extra cooling?
 
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My 'ideal' would be a Fridge/Freezer where you can control each section separately down to the extent of turning each off if you wanted. The closest I know of to that is to get separate units. The issue then is finding a suitable pair that will fit in the limited space as two units will be bigger than a single device. I dropped into a local electrics shop at lunchtime ... they didn't have a single Fridge/Freezer that was physically small enough to fit. Even the 'big' Motorhome fridges are still compact in terms of house size.
The power consumption becomes key not in the summer but if you are a winter camper and you might then turn off the freezer then if possible to save energy as the need could be a lot less.

In the camper I never turned off the fridge as the solar kept up without an issue even in winter. Fridge Freezer is twice the power use :(
 
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