Boiler pilot light went out

Our boiler pilot light went out today. Not sure when - the heating was working this morning, but wasn't by about 2pm when my wife got home and turned it back on.
I had some trouble getting it to stay lit - I kept the gas button pressed in for 30 seconds as per the instructions, but it didn't stay lit when I stopped pressing it. In the end I turned the boiler thermostat to something other than 'Off' (which the instructions said it should be on). When I released the gas button, the main burner fired up and it stayed lit. When the main burner turned off later, pilot was still lit. :)
Now - any idea what may have caused this? Problem with the boiler I would assume - the chance of the gas running out is low. Its an old Baxi wall mounted boiler.
When I'd got the boiler working again, I saw that the burner would pulse orange. It would be blue, then you'd hear a bit of a 'woosh' and it went bright orange (whole burner) and then went blue again. It kept doing this on a 5 second or so cycle. After its been on for a couple of hours, its burning continuous blue again. Oh, and when it went 'woosh' you could see a little puff of something come out the whole where the top thermocouple comes out - which worried me.
Therefore I've booked the boiler in for a service on the 3rd Nov - its the first time we'll have had it serviced since we moved here in May. Looks like its not been serviced in a while (though the pilot thermocouple looks quite clean and shiny!). We've had a little CO check thing next to the boiler, and it hasn't gone dark. Since noticing the puff of something, I moved the CO check thing to just above the thermocouple hole and I think its gone a little darker than it may have - but its certainly not "grey or black" as the thing says to check for.
So - any initial thoughts about the cause of the pilot light going out? Any problems you think I've got with my boiler? I certainly don't want to have to replace it!
I was already planning on getting it serviced - just made sure I did it now!
Thanks
D
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in
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Wind up your flue. If it is an old style boiler, then get the flue checked out to see if it isn't being effected by the wind.
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Possibly the pilot light thermocouple starting to fail. Get a universal one from your nearest shed or plumb centre. Under a tenner and a few minutes to fit. Best to keep a spare handy anyway as they only last a few years.

Waste of time having boilers serviced IMO. While the boiler is running tap the gas pipe where it runs into the burner a few times with a lump of wood. That'll dislodge any crap in it. You'll see the flame flare orange each time you do it and then it should settle back to blue. As long as the flame is blue everything is fine.
Dave Baker - Puma Race Engines (www.pumaracing.co.uk) I'm not at all sure why women like men. We're argumentative, childish, unsociable and extremely unappealing naked. I'm quite grateful they do though.
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----- Original Message -----
Newsgroups: uk.d-i-y Sent: Friday, October 24, 2003 8:43 PM Subject: Re: Boiler pilot light went out

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Are they really universal? I just want to make sure. We had our old boiler serviced (requirement of house purchasers) and they replaced the thermocouple at a cost of 15 or so. I've seen them in Screwfix for about 4. If I was to buy 2 (just in case they wanted to replace both) - what's the chance they'll use my ones? If I can get two for 10, that's better than potentially being charged 30 + VAT.
As for fitting it myself, from what I can see, I'd need to take the front of the boiler itself off to fit the thermocouple - something I don't really want to do. I have a healthy trust for gas etc - and whilst I may well be able to do things with it safely (if asking the right questions and taking it slowly) - I'm certainly not 'competant'.

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My parents never had their boiler serviced (at least, AFAIK), and I'm inclined to do the same. However, as we didn't have the boiler fitted, its old, and it does sometimes burn yellow and things (slight bang from it sometimes - I think when the boiler turns off possibly) - I'd just like it checked (maybe pressure checked etc) and then from then on, keep an eye on it myself.
Thanks
D
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You'll probably find a sticker somewhere on the boiler that lists the BTU output at different gas pressures. It doesn't make a scrap of difference what the pressure is other than affecting the heat output. A friend of mine is a Corgi gas fitter. He told me years ago that although a fair chunk of his income came from boiler servicing it was the biggest con in the business from the customer's point of view and the easiest 50 he ever makes. If there's no actual fault with a thermocouple or other component all he could do himself was hoover out any dead insects and dust and tap the gas pipe a few times to dislodge any crap and that's what he advised me to do. My boiler has been here (potterton RS50) since I bought the house 17 years ago and was several years old then. It's never been serviced other than as above and works as well now as it ever did. I've put two thermocouples on it over the years which is a 10 minute job and I've no doubt saved 17 x 50 on servicing which is more than enough to buy another boiler if this one ever goes wrong.
You only have to remove the sight glass to change the thermocouple and it doesn't involve going anywhere near any gas fittings. Anyone reading a DIY group that owns a couple of spanners ought to be able to do that easily enough. If you're worried about buying the right thermocouple then tell the shop your boiler model first.
Dave Baker - Puma Race Engines (www.pumaracing.co.uk) I'm not at all sure why women like men. We're argumentative, childish, unsociable and extremely unappealing naked. I'm quite grateful they do though.
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IMHO, it's equally likely the pilot jet is dirty so not allowing the correct sized flame and therefore easily blown out. I'd clean it first.
--
*Generally speaking, you aren't learning much if your lips are moving.*

Dave Plowman snipped-for-privacy@argonet.co.uk London SW 12
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The crap is likely to be soot deposits on the surfaces of the heat exchanger, not anything inside the gas pipe itself, and where's the crap going to go? When you decoke an engine to you dump the stuff you scrape off inside the cylinders or the sump? :-)
And if there's fluff bunging up the airways of the burner percussive maintenance isn't going to help either!
From the OP's description this machine needs proper attention.
-- John Stumbles -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -+ The most dangerous component in a car is the nut that holds the steering wheel
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