"thirty-six" wrote in message
...

On Dec 17, 4:39 pm, "Gareth" wrote:
I posted a while ago about radiators heating up when the central heating
is
turned off but just the hot water is turned on (conventional boiler).

I've realised that the radiators are also heating up - almost all of
them -
when their thermostatic valve is switched off.

It seems too much of a coincidence that every thermostatic valve - about
8
of them - could be faulty.

Does this sound like a reverse circulation problem?

Sounds like you are without a bypass loop in your heating circuit.
Thermostatic radiator control valves do not necessarily have a
positive shut-off positon and those will lift given sufficient
pressure from the circulating pump.


If so is there a way of fixing it without causing too much disturbance to
pipe work?

Take the conrol head off the rad nearest the boiler, so it's on all
the time, and control its actual output with a towel.

Thanks guys for the replies - much appreciated.

This last comment about keeping the rad nearest the boiler on all the time
has made me remember something I had forgot.

When we moved in the previous occupant had left an instruction sheet with
the boiler saying one radiator must be left on full all the time (the one in
the bathroom nearest to the boiler). Why would this be?

You've said the same thing. Does opening that radiator reduce the pressure
flowing in to the other radiators?