First apologies - I am sure I have seen a similar question in the past, but
couldn't find it for some reason...

Problem as per subject:

Recently, despite having the heating off, some (not all) of the radiators in
my house are hot when the hot water is switched on.

As you probably guessed by now, I am no expert on the subject, but I believe
the system is a conventional one, based around an ageing ServoWorm Elite 80
boiler (to be replaced next year when the extension is to be built).
One possible clue it that we had to have a pump replaced in it last year
when we bought the house when we realised that the only way to get hot water
was to turn the heating on...
Also, both heating and hot water seem to work OK apart from the hot
radiators getting warm.

Any idea what is going on?

Thanks in advance.

sounds like a diverter valve stuck
"JoeJoe" wrote in message
...
First apologies - I am sure I have seen a similar question in the past,
but
couldn't find it for some reason...

Problem as per subject:

Recently, despite having the heating off, some (not all) of the radiators
in
my house are hot when the hot water is switched on.

As you probably guessed by now, I am no expert on the subject, but I
believe
the system is a conventional one, based around an ageing ServoWorm Elite
80
boiler (to be replaced next year when the extension is to be built).
One possible clue it that we had to have a pump replaced in it last year
when we bought the house when we realised that the only way to get hot
water
was to turn the heating on...
Also, both heating and hot water seem to work OK apart from the hot
radiators getting warm.

Any idea what is going on?

Thanks in advance.

JoeJoe wrote:
First apologies - I am sure I have seen a similar question in the past, but
couldn't find it for some reason...

I'm sure you have - this comes up quite often ;-)

Recently, despite having the heating off, some (not all) of the radiators in
my house are hot when the hot water is switched on.

So it used to be OK (ie you could heat heating and hot water
independently), right? Just that if not, it's possible you have a
really cheapskate system which was not intended for them to work
independently, ie in summer you just turn all the rads off manually or
turn the roomstat down really low to force 'always off'.

As you probably guessed by now, I am no expert on the subject, but I believe
the system is a conventional one, based around an ageing ServoWorm Elite 80
boiler (to be replaced next year when the extension is to be built).
One possible clue it that we had to have a pump replaced in it last year
when we bought the house when we realised that the only way to get hot water
was to turn the heating on...
Also, both heating and hot water seem to work OK apart from the hot
radiators getting warm.

More likely - assuming you did used to be able to isolate the CH - is
that you have a failed 3-way motorised valve, something like this:
http://www.screwfix.com/app/sfd/cat/...43961&id=53314.
See if you can find one - probably near the HW tank if you have one?
They normally have a small sliding lever which you can actuate manually
to over-ride the built-in motor, so if the motor has failed you should
be able to tell by mimicking its action this way. Have a look at the
FAQ, which explains all about how these work IIRC.

If the motor has failed, you should be able to replace just the motor on
its own without removing the whole valve and draining the CH system,
which is a much bigger job.

David

In an earlier contribution to this discussion,
Lobster wrote:


More likely - assuming you did used to be able to isolate the CH - is
that you have a failed 3-way motorised valve, something like this:
http://www.screwfix.com/app/sfd/cat/...43961&id=53314.
See if you can find one - probably near the HW tank if you have one?
They normally have a small sliding lever which you can actuate
manually to over-ride the built-in motor, so if the motor has failed
you should be able to tell by mimicking its action this way. Have a
look at the FAQ, which explains all about how these work IIRC.

If the motor has failed, you should be able to replace just the motor
on its own without removing the whole valve and draining the CH
system, which is a much bigger job.


It *could* be a problem with the mid-position valve (if you have one) but
it's unlikely to be a failed motor. The motor moves the valve *from* the HW
position to the 'mid' and CH positions - and a spring returns it when the
motor is turned off. If the motor fails, the valve stays in the HW position
and you *don't* get warm radiators. If it *is* the valve, it's more likely
that the mechanical part of the valve is stuck or that the spring return
isn't working.
--
Cheers,
Set Square
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