On Tue, 10 Apr 2007 01:35:16 -0700, iceland_potter wrote:

Thanks Ed and Stuart,

Ed - sounds like it could be that, although when I turn the hot tap
on, there is immediately a burst of hot water, then it goes lukewarm
at best for sustained periods of time.

Stuart - Why would I be a troll? I have a problem with my boiler, so
I posted to a diy usenet group, please explain why you think I may
have been a troll?

I have put more water in the boiler from cold though to raise the
pressure to 1.2 bar, this seemed to work for a bit then after a day or
so I'm left with the lukewarm-at-best problem as described.

The most likely failure modes a

1) The water flow diaphragm has partly split is becoming less sensistive
and effective, whilst it still switches the boiler on it is not strong
enough to move the valve fully to the DHW position.

2) Due to anyone of a number of problems the diverter valve is too stiff
to shift to the DHW position.

HTH

--
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
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards