Whistling Boiler

My Vokera Excell 80E combi boiler occasionally starts whistling when the central heating is on. I can stop the whistling instantly by turning on a hot tap for a couple of seconds. The whistling goes away but always comes back at some point. Some days it will come back in a few hours, other days it won't whistle much at all.
Please can you tell me what the problem might be and also what to do to fix it.
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On Mon, 01 Dec 2003 11:41:47 +0000, anon wrote:

Possibly it is some form of 'kettling'. That is localized boiling in the heat exchanger.
There are various chemicals to add to attempt to cure the effect, only one of which IMHO is any good that's the boiler silencer gel form Fernox (30 quid a shot).
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
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Teach it to sing
Sounds like a washer, but could be a range of things. I think you will have to locate it a bit more precisely. Probably not dangerous (Boom)
--
geoff

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Ours does this all the time until it's warmed up. It sounds like a hurricaine in the kitchen until about 15 mins into a cycle then it quietnes down. It's been regularly serviced and checked and double checked - it just does it.
There's a fair bit of noise from the gas influx to start with - but it clanks and whistles while it gets up to temperature and two separate engineers have told me this is safe and ok to use....
Might try some of the stuff that Ed suggested tho - was reading about it...
Cheers Dan.
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It is either bored, or very happy in its work.
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