Plumbing Problems in the UK? Ask a Plumber Now.
Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Please provide all information I request as it makes it more difficult to troubleshoot something when I'm not there onsite. Essentially, you become my eyes and ears. Thanks for the opportunity to help. At the end of our dialog, you will have a chance to rate my service, but please wait until we are finished and you're satisfied you have all the information you need. Please be patient as many times we work with several customers at once.
I see none of our experts have picked up your question yet. Couple things: is the pilot flame strong, blue, and enveloping the last 3/8 inch of the thermocouple? Does the boiler have a good wind cap at the top of chimney outside?
So it sounds like it is a gas supply problem, then. Has regulator been checked?
Unfortunately just stating "doubt if it's the regulator" is not getting us anywhere. We need to look at all the things that cause a pilot to go out and actually eliminate them one by one. Typically the most common reason a standing pilot goes out is a bad thermocouple or poor pilot flame. The output of the thermocouple can actually be measured using a meter and a thermocouple adapter. These should put out between 25-30 millivolts. The next thing if this checks out OK is a bad gas valve. Sounds like that's been replace, although it's always possible to get a defective valve. Low pressure or gas pressure problems can also cause pilot outages. Finally if pilot goes out intermittently, a downdraft through the chimney can blow pilot out.
Could be blown out by wind coming down chimney, OR when boiler is lighting (or burner shuts down) could be doing it with such force it blows pilot out. Or, as I said, could be a pressure problem and this can be measured with a device called a manometer.
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