Radiators hot when heating turned off!

[elainela]

The hot water timer is set to come on twice a day for an hour at a time, however it was accidently switched on all night at the weekend. The radiators normally heat up when the hot water is switched but now with the hot water off they are still warm. I have not had the hot water on since Sunday evening and I ran the hot water tap until it went cold but the radiators are still hot, its as though the heating is on even though the timer says its off.

 

[Agile]

Sounds like a failed motor valve!

Tony

 

[pgod3]

i agree motorised valve head has jammed open

 

[elainela]

How big of job will this be to fix?

 

[75pete]

Some types of valve can be changed without the need to drain down the whole system, it could be just the motor headof the valve thats failed and new head could be fitted without the need to drain.
How much? Well is it easy to get at? Is it the head thats failed? or is the valve in need of a change and your system may have to be drained and new valve fitted / system refilled and bleed. Have a look at the valve and post the make etc.
A nice plumber would do it for.............

 

[Agile]

In London we charge £84 diagnostic fee plus £34 to fit a now motor if thats possible.

More if the head or whole valve has to be changed.

Tony

 

[Londoner]

I have a similar problem. Where generally would the motorised valve be?

I have a Grundfos pump installed - does that contain the valve that is failing and letting hot water into the rads?

 

[Agile]

The motor valve(s) is where ever the installer chose to put it.

Usually near the cylinder or boiler though.

Try looking at other posts or the FAQ so you can see what they look like!

Tony

 

[Biguns]

The hot water timer is set to come on twice a day for an hour at a time, however it was accidently switched on all night at the weekend. The radiators normally heat up when the hot water is switched but now with the hot water off they are still warm. I have not had the hot water on since Sunday evening and I ran the hot water tap until it went cold but the radiators are still hot, its as though the heating is on even though the timer says its off.

Im sure its me (the old timer) reading this wrong. But I still interpret that with everything switched off (No hot water demanded since sunday) the CH is still coming on. The CH normaly comes on with the HW. Gravity system?
What am I not seeing here?

 

[Nige F]

I think you ARE seeing parasitic circulation

 

[Biguns]

OK one pipe system, as the OP says everything switched off and radiators still warm. How is it the motorised valve ??

 

[lifesagasman]

i want one! no-cost heating...

 

[Londoner]

After a BG inspection, it was suggested sludge was preventing the valve from working properly. Had a Magnaclean installed which shoyuld fix the problem.

I was concerned I was being talked into buying a bit of useless kit but from what I've read online, it's a genuinely useful gadget and the sludge probably was the source of the problem (I hope)