Hi I've got a Main water heater. It started playing up and the pilot assembly was changed; all OK for a while. Then played up again and the gas valve was changed; all OK for ten days.
New years Eve it went out. I can get the pilot light to light, but is goes off when I release the knob. Any ideas? I remember the plumber saying there was only one more part that can be changed! Only notvceable thing is that the pilot light has a bit of yellow in the blue of the flame.
Andrew (in need of a shower)
If the pilot light goes out, then IMO either the thermocouple is faulty, or the pilot light orifice is a bit clogged up and isn't delivering enough pilot light flame to allow the thermocouple to keep the pilot light gas supply turned on.
Options are to: (1) Clean the pilot light orifice(s) out using an appropriate tool ( stiff brush ? ). (2) Replace the thermocouple, reputedly an easy and cheap job.
Take all necessary safety precautions or get someone in who knows what they're doing blah, blah,
Andy.
Four possibilities..
The pilot light should not be yellow, though it should not affect its staying lit.
The thermocouple is a device which generates a small current when it is heated. It looks like a thin copper pipe (though not actually a pipe), one end bolted into the gas valve, the other end has a tip intended to be in the pilot flame.
Models which are less than 10-20 years old will have an over heat protection device in series with the thermocouple.
For some reason these devices seems to go down with an intermittent fault. They are simple self resetting overheat cutouts. Black plastic (c. 15mm diam x c. 7mm thick ) with a couple of spade connections and a metal plate with a couple of small holes to screw it in location.
They are a few quid to obtain and a few minutes to change.
After the thermocouple this would be the next item to eliminate.
Hi Andrew
If the pilot won't stay lit when button released and since both gas valve and pilot has been change it could be the thermocouple worn, not located correctly or not tightened. Some modals are fitted with overheat stats. If faulty the pilot won't hold.
If the pilot assembly has been replaced it should burn blue without any yellow whatsoever. If the pilot burns yellow it will not be stable and won't produce enough heat to energise the thermocouple. Could be a bit of dirt in the pilot or its not correctly fitted.
It is illegal for any person other than a CORGI registered engineer to work on gas appliances. This is also to ensure your and others safety.
David (corgi engineer)
Not necessarily so on two counts:
1) If it's your own property, and not for any financial gain, it's not illegal, so long as you are "competant" to do the job. 2) Using a CORGI does not *ensure* safety (many of us have seen terrible bodges by CORGIs), but I'm sure it is statistically safe than getting in some cowboy non-CORGI plumber who does a bit of gas on the quiet.Jon.
I agree with Jon. Whether you are 'competent' is not defined in law, so it's rather a matter of if you get it right, you're competent, if you get it badly wrong and there are consequences, you're not competent! I fitted my own boiler, lots of regs to comply to and tests to do but within the scope of the serious DIYer.
Andy.
david west brought next idea :
Oh no it isn't!
Another possibility is that the over heat device is doing its job and cutting out due to the heat exchanger getting too hot. This could be caused by the gas valve sticking open. I had an old Main Medina (predated the over heat device) destroy itself this way.
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