Hi all,

Parents are away in austria and the the person who is dogsitting for them
rung the other day to say that the heating has gone wrong.

She claims that on wednesday the boiler ran all day and night - this is
believable as it used 4 skuttles of coal - it would usually only have 1 - 1.5.

I managed to drive over and take a look on thursday my which time water was
running out of the overflow from the central heating expansion tank.

A quick look in the loft revealed that the ball on the valve in the
expansion tank was full of water and therefore not floating (quick bodge
with empty bottle sorted that for now as I had no tools with me and it
was 10pm) but I can' see anything wrong with the boiler.

There was a lot of condensation on the insulation on the expansion tank
which suggests that it was pumping over at some point but it was cold when I
got there (even though the heating had been on all day). The constant
trickle of cold water running in from the knackered ballvalve would have
cooled it down though I suppose.

Anyway, valve is obviously toast - could this have been damaged by sitting
in a steam filled expansion tank? Seems too much of a coincidence.

I'm assuming that the ball valve couldn't have caused the boiler to run
permenantly? I can't think of a way that this could happen...

Finally, is it likely that the thermostat in the boiler went wrong (thats
happened before) but then somehow "fixed" itself? Dodgy connections aside,
this seems an unlikely failure mode - views?

I'm coming to the conclusion that when the dogsitter filled the boiler on
tue eve and empty the ashes she didn't manage to shut the fire door
correctly and the constant draft made the boiler sound like it was running
all of the time, boiled the water (she says it was *very* hot) and this
hot water knackered the ball valve. Plausible?

Of course, its probably just getting ready to expire on Xmas eve...

Cheers,

Darren