Back Boiler Problem

Please can somebody help me? I have a back boiler / gas fire combination ( Thorn Housewarmer e ). The problem that I have is that I cannot get the pilot light to stay on. The instructions state - make sure the central heating is switched on, hold the pilot light switch and press the ignition. Then hold the pilot light switch until for approx 20 secs and then gradualy release. This should keep the pilot light on. However I have tried this numerous times but it just go's out! I have replaced the thermocouple, but again to no success. This problem has only just started occuring. I had the system working yesterday but the back boiler kept going out intermittently and now it wont come on at all. Any idea's. I have a danfoss CH terminal. When the on switch was depressed the whole back boiler came to life, but now it clicks but seems it doesnt do anything else. HELP!!
Thanks,
Darcy
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It sounds very like the thermocouple, which tells the main gas valve that the pilot flame is lit, has gone faulty. Have a web search for spare parts on your make and model of system, or for a supplier of a universal thermocouple.
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parts
OP says (s)he's already replaced the thermocouple!
For the whole thing to work, the pilot has to heat the thermocouple - which, in turn, tells the gas valve that all is well and allows the boiler to fire.
If this is not happening, it could be caused by any of the following: * Duff thermocouple (unlikely, since this has already been replaced) * Incorrectly connected thermocouple * Faulty pilot flame (crud in the jet, or pilot pressure regulator set too low) * Thermocouple not aligned properly (so that it's not being heated properly by the pilot flame) * Duff gas valve
Working through that lot should hopefully find the cause, and fix it.
Roger
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On Thu, 04 Dec 2003 15:30:32 +0000, Roger Mills wrote:

Agreed. Make sure the you have preperly eliminated the first four before considering the gas valve.
On many models you can feel whether the is some 'stickiness' in the release button. If you can feel some but it is not enough to hold the flame on then I'd suspect the thermocouple, or not in the flame, or not enough flame. If you feel nothing at all then a loose connection. Note that the connection of the thermocouple to the gas valve is quite awkward and easy to get a misconnection.
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Ed Sirett - Property maintainer and registered gas fitter.
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I have changed the thermocouple, made sure the boiler was clean and checked the jets. However none of them seems to of helped. I have managed to get the pilot to hold once but when I have then switched the CH on it just clicked and the back boiler didnt come to life. Before when the CH was switched on there would be a sort of whooshing noise then the back boiler would ignite. I dont know what to do next. I have also searched the net for spares for the make of back boiler but to no avail, can any one help me here, please.
Thanks for your help so far gents.
Look forward to your response.
Craig
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Sammer1_uk wrote:

If you're sure the thermocouple is ok for your boiler and it working, then it sounds as though the gas valve may be faulty. I don't know these boilers but it proberly works like this... The thermocouple, when up to temp, will latch on the gas valve to keep it on, thats why you have to hold it in for some time. Then the main part of the gas valve will open when there is demand voltage on it. The click sound may be the gas valve trying to work. The whoosing noise is the initial ignition of the main burners. It also possible that there may be some muck in the gas inlet at the boiler. Often there is a small strainer in there. If it is the gas valve there are only a few makes of those used by most boiler manufacturers. Changing one of these is not for the faint hearted though..
The people at http://www.cetltd.com may be able to help.
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