Can't turn heating off

[vicars]

I have been having problems with my heating and radiators and have eventually replaced my Honeywell 3 port valve. The problem I have which still happened before replacing the valve was that with the hot water on the central heating in the whole house comes on as well. The valve does not seem to isolate the two despite physically moving (the valve overide spring returns to its off position). I have a coil indirect cylinder, gas boiler and a 2 storey house. Could it be the timer board where you select whether hot water comes on or off, twice or continuous etc?) Pleae help!

[BillyNoMates]

If the problem was there before you replaced the 3 port valve, and you have confirmed that the new valve is working OK, then it is not plumbed in correctly. Seen it many times - plumbers are great at connecting pipes together but not so good at working out the logic. (No disrespect to plumbers) So my reckoning is the pipework is not routed correctly. It could possibly be that the valve is working in the wrong way. I.e. it is electrically wired incorrectly to the controller. Honeywell do a pretty good data sheet for the electrical side. Pipework you'll have to trace out yourself. Unliely to be the controller. As a long shot, unlikely given your question and info, you may have a bit of crap in the new valve which is stopping it closing properly.

[vicars]

Thanks for the reply but the problem seemed to happen over time. Everything used to work properly but then the radiators didn't heat up properly, came on intermittently and then stopped working. I changed the syncron motor which worked briefly but then it failed again and so I turned all rads off over the summer. When checking out the syncron motor again recently I blew the electrics in the 3 port valve and so replaced it with a new valve - could it be that something is wrong with the wiring where the valve joins the board in the airing cupboard?

[BillyNoMates]

Sounds quite possible. Is there a way of manually setting the value in position ? Most have a lever on the side which can be moved and locked into the 'energised' position. Try that and see if it seperates the hot water flow. If so, then it looks more like a wiring issue.