Radiators get hot when on hot water only.

[diydoolittle]

Hiya have had a problem with my heating since Monday. You can have it on hot water only or hot water and central heating. Currently the heating is off (too hot here in Sunny Scotland for once) but the radiators are boiling hot. This is despite thermostat being down at about 10!!!! On Wed central heating company changed the valve which is on top of the pump, but the same thing is still happening. So what on earth can this be? Anyone able to hazard a guess. Boiler is not a combi. Think it's a gloworm.

 

[ollski]

Probably just changed the valve head rather than the body hoping a stronger spring might keep the valve closed.

 

[diydoolittle]

He put on a new silver box thing from Honeywell but not the pipe that came with it. Does that make a difference. Sorry not technically minded as you can no doubt tell. The box thing has a cable coming from it which goes into a box/socket thingy on the wall he didn't put the screws back on so I screwed them back in. Could this have done something

 

[gas4you]

I doubt it. Either he has wired it incorrectly or the valve body may be stuck. Can't believe someone would not put the wiring centre cover back on

 

[diydoolittle]

Thank you to both of you for your replies. He did try to test it before he left. He asked my OH to switch on heating only for a minute then switch off. Then put on again for 30 secs. This must have done nothing ecause he came hairing downstairs to put thermostat up as it was down at it's lowest setting. The OH repeated the above. Thing is after I thought about it the problem only occured when only the Hot water was on. Anyway they are coming back tomorrow so will see what they say. will update as soon as I know.
Thanks again for your very quick responses.

 

[diydoolittle]

Probably just changed the valve head rather than the body hoping a stronger spring might keep the valve closed.

Yep that is exactly what he did. New chappies drained whole system and put on yet another new valve plus the body as you have said above. They also fixed a shelf in the airing cupboard (where the pump is) which they didn't need to do, so now all sorted. Thanks for your help.