"raden" wrote in message
...
In message , Roger Mills
writes
In an earlier contribution to this discussion,
Mike Lane wrote:

My system has started playing up. We noticed it when the weather
turned warmer, and we turned the heating off. But the heating stays
on regardless even if we also switch the water off at the timer (a
Honeywell 7 day water and heating model). Basically, the pump
continues working and the boiler fires up. The only way I can get
things to stop is to turn the timer off at the mains. I have
disconnected the frost stat to no avail, so that can't be the problem.

Any help would be appreciated. Thanks

The most likely diagnosis is that you have a zone valve which is either
stuck open - even when turned off at the programmer - or the micro-switch,
which provides its auxilliary contacts, has failed shut. [I am assuming
that
you have an S-Plan system, with separate 2-port valves for HW and CH
rather
than a Y-Plan system with a single 3-port valve?]

Someone else reported a similar problem recently which turned out to be a
failed pump over-run stat on the boiler. I have to admit that I'm
struggling
to understand how this would make the boiler fire - rather than just
running
the pump continuously - but it's nevertheless something else to check.

Possibly that's what the OP (Caps lock stuck) meant

he could just hear something asking a noise

ISTR he gave no indication as to what the boiler was, making it difficult
to know much more (e.g. it's a well known problem with the baxi solo 2
pcb)

--
geoff

Hi

Seems like the problem is a stiff Honeywell motorised valve on the heating
side. I took the cover off and forced down the mechanism. Now, the pump has
stopped and I get the resistance on the lever at the top. However, I think
that when the water comes on, the pump might reactivate again. But at least,
I can leave the programmer powered up without the pump coming on
automatically.
Is there a way of lubricating the valve or do I need to replace it? Thanks
to all of you who took the trouble to respond to my original post.

Mike