"Stuart Black" wrote in
:

Thanks Mike,

Valve is working, I think the boiler is overheating as it seems far
more active than normal.

The primary feed into the cylinder is getting hot, as is the feed out
after a while, but the coil is having nowhere near the heating effect,
both in temperature or voume of heated water.

I still suspect that the removal of the radiator is the cause but it's
not an obvious problem to diagnose. Any thoughts on how such an act
could cause the hot water feed to become ineffective ?

Stuart

I've got to say I haven't a clue.

Ican't see how removing the radiator has done anything, unless it
drastically changed the C/H circuit.

Rads are usually wired in parallel across the main boiler pipes so removing
one should not affect the circuit too much - is it possible yours are in
series, so you've blocked the circuit (very unlikely)?

Have you got TRVs on the rads, which are closed due to the summer
temperatures? Can you adjust them to get flow?

In any case, I can't see how this would affect the totally separate HW
circuit.

I forgot something - are the rads getting hot, because of demand from the
room stat, or perhaps a fault, so that the lack of hot water is because of
hot rads?

Have you got a bleed valve on the primary - sorry, I forgot, you have, and
it works - just make sure you have a nice steady squirt of water from it
after a bit, not "fizzing"

When all is said and done, I can't see how your boiler can pump 1215 kW
into your tank without something blowing after about 1/2 hour or so. And if
the boiler safety stat isn't cutting out pretty quickly (short cycling) the
heat must be going somewhere, the boiler stat would cut very fast if it
weren't.

FRankly all the above is very speculative, I had hoped some of the more
knowledgeable folk would take up your problem, it was either something you
said, or perhaps theyre baffled! I don't quite see how to get their
attention, they can't be forced to reply.

That's the best I can do unless I think of something else; I hope you find
the answer soon,

mike