In article ,
Mike Faithfull wrote:
"Dave Plowman (News)" wrote in message
...
It does indeed sound like the overheat stat has failed, and shouldn't
cost much to have replaced on spec, even although it appears to work
sometimes - like when the engineer calls.

But you could just turn the boiler down initially to perhaps 80C or so
- it doesn't need to be full up for just heating the water.

Thanks Dave. It was, actually, on a lowish temperature setting already
(and 50 to 82 degrees is allegedly the control range).

So it looks like two faults.

I have investigated further my looking at a parts list in the
installation manual, and the temperature control systems seems to be a
little more sophisticated than a straight old-fashioned on/off
thermostat, using as it does, a thermistor sensing element, and a
potentiometer which are connected to an electronic control board. As
BOTH functions seemd to be dodgy (temp control AND overheat) it might be
something as simple as one (or more) of those grotty spade connectors
that has corroded over the years. I'll ask my man when he comes to
remove and replace the connectors a couple of times. Can't do any harm
and may do some good!

I'd expect it to be more sophisticated than my Kingfisher which I changed
only a couple of years ago after some 25 years of near faultless service.
Sadly, Potterton lost the plot reliability wise.

--
*A backward poet writes inverse.*

Dave Plowman London SW
To e-mail, change noise into sound.