On Thu, 24 Feb 2005 15:04:39 +0000, diaj wrote:


Hi,

I've got a Vaillant VCW combi boiler. The pilot light on this has
started to put itself out several times a day - what seems to happen is
the gas coming on when the boiler fires up (e.g. when you turn on a hot
tap or the heating) occasionally puts out the pilot. I have insurance
cover whereby if the heating/hot water breaks my insurance company will
send someone to repair it; however, when I spoke to them on the phone
they said they'd only do this if I first wait until the pilot light
*always* goes out when the boiler fires up. I therefore thought I'd
check if it's likely to be anything obvious/easily sorted.

Have checked that the temperature the boiler's set to is appropriate
for the (lousy) weather, and the only thing that looks slightly amiss
is that the pressure is down to just over 0.5 bar - this is above the
0.5 bar recommended minimum, but only *just*...is it worth trying to
raise the pressure and seeing if this helps matters? And can this be
done by just turning a valve marked 'filling valve' to 'open', or is it
more complicated than that?

As for filling the boiler see the FAQ below.

The three most likely reasons for the pilot going out a
1) The boiler's over heating (or it's sensor thinks it is).
2) There is a poor flame on the thermocouple and a bit of draught causes
it to cool down a little too much.
3) The thermocouple is dying.

If you find that you can release the 'start' button within a few seconds
after lighting the pilot - i.e. you don't need to hold it in for the full
20s or so to light it ... then I think 2 or 3 are less likely.

The t/couple is a custom unit on these boilers around £10 instead of £4,
because they incorporate the connections to the Over-heat cut out.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html