The gas ring can be lit but when you release knob controlling gas the gas goes out lite again and sometime stays a lite . any ideas what indeed to do? Just unrealisable.
Dougwe said
04:08 AM Jan 3, 2021
You need to hold the knob in for a few seconds after it lights up Keith.
I'm probably stating the obvious though.
Keep Safe on the roads and out there.
edit.... Just remembered, Check the gas flow is good as I had to adjust the gas regulator at the bottles as not enough gas getting through. Well I didn't but a gas person did.
-- Edited by Dougwe on Sunday 3rd of January 2021 04:12:31 AM
Mike Harding said
06:34 AM Jan 3, 2021
This is also a problem with my two year old Thetford cooktop and I am not at all happy about it.
Next to each gas burner there is a vertical rod about 15mm high (thermocouple) try cleaning this as best you can with a rag and/or steel wool. If you're lucky this will let the burner operate again but sooner or later a replacement will be required. The first failure on my cooktop occurred at about 9 months and a second burner is now on its way out. Eventually I'll strip the unit down and see if I can bypass this "safety" feature or replace it with a different (non bloody Thetford) thermocouple.
Possum3 said
10:02 AM Jan 3, 2021
Mike you will void insurance also risk fine/s by removing "thermocouple". As these stoves have been involved in several fires it would be prudent to only have a licenced gasfitter attempt rectification/replacement.
Mike Harding said
04:34 PM Jan 3, 2021
Sadly Possum... I am not a prudent man... I guess that's much of the reason I live in the bush in a caravan...?
Triggy said
12:29 AM Jan 5, 2021
jeepnudger wrote:
The gas ring can be lit but when you release knob controlling gas the gas goes out lite again and sometime stays a lite . any ideas what indeed to do? Just unrealisable.
Make sure the glass top lid is fully up as there is a safety switch on the rear hinges that stop the gas if the lid is not up fully.
This has caught many unwary people.
JWH said
04:02 PM Jan 5, 2021
Most Thetford products have Flame Failure devices as discussed previously, however, cleaning the probe in the burner will only work if there is a very evident build-up of soot from poor combustion.
That probe (Not the white one) is a thermocouple that generates approx. 30 millivolts when heated.
The knob / valve you are pushing in has an electromagnet inside, so when you push it in, it opens the gas flow and makes contact, the voltage from the thermocouple is sent to the valve you are pushing in and will now hold the electromagnet together. The magnet should now stay together whilst the burner is lit. (No flame, no heat, no voltage, no gas flow).
Unfortunately, Thetford use a co-axial (Like your aerial) type of connector at the valve end and because of such a low voltage, it requires a good earth. Sometime that earth is where the thermocouple mounts to the hob, but mostly it is through the co-axial connection, and over time it simply loses the connection, so the connection points need to be cleaned. (replacing it generally involves cleaning the connections anyway, so it appears to be what fixes it).
Mostly (If you can access the thermocouples at the valves) all you need to do is turn the co-ax connection about 5 degrees each way to clean up the connection, no further or you may damage it, and lit they will stay!
Mike Harding said
05:29 PM Jan 5, 2021
JWH wrote:
Most Thetford products have Flame Failure devices as discussed previously, however, cleaning the probe in the burner will only work if there is a very evident build-up of soot from poor combustion.
That probe (Not the white one) is a thermocouple that generates approx. 30 millivolts when heated.
The knob / valve you are pushing in has an electromagnet inside, so when you push it in, it opens the gas flow and makes contact, the voltage from the thermocouple is sent to the valve you are pushing in and will now hold the electromagnet together. The magnet should now stay together whilst the burner is lit. (No flame, no heat, no voltage, no gas flow).
Unfortunately, Thetford use a co-axial (Like your aerial) type of connector at the valve end and because of such a low voltage, it requires a good earth. Sometime that earth is where the thermocouple mounts to the hob, but mostly it is through the co-axial connection, and over time it simply loses the connection, so the connection points need to be cleaned. (replacing it generally involves cleaning the connections anyway, so it appears to be what fixes it).
Mostly (If you can access the thermocouples at the valves) all you need to do is turn the co-ax connection about 5 degrees each way to clean up the connection, no further or you may damage it, and lit they will stay!
Very, very interesting and I am almost sure inside information for a first post JWH - thank you.
Thetford need to get off their arse and fix it! And offer to fix it for those of us who's cooktops failed at just a few months old - nowhere near good enough, is it?
Edit:
>however, cleaning the probe in the burner will only work if there is a very evident build-up of soot from poor combustion
Interestingly, no. Cleaning the probe with a rag or similar causes the system to operate again for a time (days or weeks?) and I have no idea why. Given the thermocouple comprises just two dissimilar wires welded together inside a metal case why this action should have an effect I do not know, but it does.
-- Edited by Mike Harding on Wednesday 6th of January 2021 06:37:19 AM
JWH said
04:03 PM Jan 6, 2021
Mike - I don't work for Thetford (I'm not sure if anyone does really ) I am but a lowly Gas Fitter who specialises in Caravans, RV's Camper trailers etc... Happy camping.
You need to hold the knob in for a few seconds after it lights up Keith.
I'm probably stating the obvious though.
Keep Safe on the roads and out there.
edit.... Just remembered, Check the gas flow is good as I had to adjust the gas regulator at the bottles as not enough gas getting through. Well I didn't but a gas person did.
-- Edited by Dougwe on Sunday 3rd of January 2021 04:12:31 AM
This is also a problem with my two year old Thetford cooktop and I am not at all happy about it.
Next to each gas burner there is a vertical rod about 15mm high (thermocouple) try cleaning this as best you can with a rag and/or steel wool. If you're lucky this will let the burner operate again but sooner or later a replacement will be required. The first failure on my cooktop occurred at about 9 months and a second burner is now on its way out. Eventually I'll strip the unit down and see if I can bypass this "safety" feature or replace it with a different (non bloody Thetford) thermocouple.
Sadly Possum... I am not a prudent man... I guess that's much of the reason I live in the bush in a caravan...?
Make sure the glass top lid is fully up as there is a safety switch on the rear hinges that stop the gas if the lid is not up fully.
This has caught many unwary people.
Most Thetford products have Flame Failure devices as discussed previously, however, cleaning the probe in the burner will only work if there is a very evident build-up of soot from poor combustion.
That probe (Not the white one) is a thermocouple that generates approx. 30 millivolts when heated.
The knob / valve you are pushing in has an electromagnet inside, so when you push it in, it opens the gas flow and makes contact, the voltage from the thermocouple is sent to the valve you are pushing in and will now hold the electromagnet together. The magnet should now stay together whilst the burner is lit. (No flame, no heat, no voltage, no gas flow).
Unfortunately, Thetford use a co-axial (Like your aerial) type of connector at the valve end and because of such a low voltage, it requires a good earth. Sometime that earth is where the thermocouple mounts to the hob, but mostly it is through the co-axial connection, and over time it simply loses the connection, so the connection points need to be cleaned. (replacing it generally involves cleaning the connections anyway, so it appears to be what fixes it).
Mostly (If you can access the thermocouples at the valves) all you need to do is turn the co-ax connection about 5 degrees each way to clean up the connection, no further or you may damage it, and lit they will stay!
Very, very interesting and I am almost sure inside information for a first post JWH - thank you.
Thetford need to get off their arse and fix it! And offer to fix it for those of us who's cooktops failed at just a few months old - nowhere near good enough, is it?
Edit:
>however, cleaning the probe in the burner will only work if there is a very evident build-up of soot from poor combustion
Interestingly, no. Cleaning the probe with a rag or similar causes the system to operate again for a time (days or weeks?) and I have no idea why. Given the thermocouple comprises just two dissimilar wires welded together inside a metal case why this action should have an effect I do not know, but it does.
-- Edited by Mike Harding on Wednesday 6th of January 2021 06:37:19 AM
Mike - I don't work for Thetford (I'm not sure if anyone does really
) I am but a lowly Gas Fitter who specialises in Caravans, RV's Camper trailers etc...
Happy camping.
All noted JWH :)
Many thank for the info.