"Andrew Collins" com.hotmail@bflfcbb wrote in message
...
Ever since we moved into this house 5 years ago we've had to top the
central heating system up more often than I would have liked. Once a
month or so.

Now it's suddenly got a lot worse, as in once per day. I've just
checked the expansion vessel. Now, the system was hot, but there was
plenty of pressure in it and no water. Unfortunately I don't have tyre
pressure gauge, but from years of cycling I would guess it was well
over 20PSI.

I've looked for a relief valve test knob but can't find any red knobs
and can't find anything that I would be confident in tweaking. Odd, I
can strip down and rebuild your average Ford engine without any
worries. With combi boilers I start getting really nervous though.

Whilst I was fiddling about with this (a period of no more than half
an hour) about 3/8 of a pint of water came out of the boiler overflow
pipe (yikes!).

The boiler is a Worcester Bosch 240.

I'm guessing that it's time to try to find a professional to fix it,
but is there anything else I can do before I go spending serious
money?

I've got some photos of the boiler that I can put on the we if that
would help.


Thanks,

Andrew

The pressure relief valve is right at the back/bottom of a 240 (drop the
control panel down to see it), and is normaly a red one with the pressure
gauge directly attached (just trace the relief pipe up to find it). It
sounds like it is leaking, thus dropping pressure - flushing it though may
help (give it a twist, then repressurise), otherwise drain the boiler and
replace (again, twist it to drain fully, no need for mains water isolation,
DO NOT isolate the boiler via its own isolation valves as these WILL leak.
Not expensive, part no more than £5, you can DIY.

Angus