Hello Anna

On Tue, 10 Feb 2004 08:06:16 +0000, Anna Kettle wrote:

I have so many things that need doing yesterday in my new house and I
had hoped to avoid doing anything to the central heating this year,
but I don't think its going to work out like that.I have never owned a
central heating system before so its a bit of a black box.

The system is 20+ years old and will be replaced in the next year or
so. It is oil fired and has microbore piping.

There are devices on each radiator which control the temperature to
that radiator. How do thay do that?

They are mechanical thermostats - often filled with liquid, which when
it expands, will push down on a valve and close off the water feed.

There is a pipe leading to the
device, then to the radiator and then another pipe leading from the
radiator onwards, so it can't be by flow control or the next radiator
down the line would be controlled too.

The radiators are usually connected in parallel across the water feed,
so each can take what it wants without affecting (well not much) the
other radiators.

As you have microbore, each radiator's pair of pipes usually go back
to a pair of water distribution blocks which are on the hot and cold sides
of the boiler respectively.

One of these devices doesn't work, so one radiator is at full blast
the whole time and thats in the guest bedroom so wasteful. Presumably
I need to replace the device?

It sounds pretty definate that it has failed.

What is it called

A thermostatic radiator valve. A popular maker is Drayton.

and does replacing it
mean draining down the whole system?

It used to. But it's possible these days to freeze the pipes both sides of
the radiator with either an electrical freezer for plumbing, or for short
intervals one can use a special freezer spray but don't run out in the
middle of the job(!). Bear in mind that the radiator itself will have to
be emptied - but that's not as bad as the whole system.

Is that worth doing at all
considering that the weather is going to get warmer and the heating
will be turned off in a month or two.

If you can wait (there's no risk by the sounds of it) then wait until the
new boiler is fitted and fix it then.

But if you're fed up with it, a plumber shouldn't make a big deal of it.

Anna

Hope that helps.