Rads hot when HW is selected

[fitz4x4]

Hi I'm a newbie poster on the site but have found a lots of intresting points reading about problems and fixes.

I adjusted my cylinder stat and noticed that the radiators are now heating up when the programmer is on HW setting. I reset the cylinder stat but the rads still heat up on HW.

Can this be caused be a faulty cylinder stat or is it more likely the 3 way valve or something else?

Thanks in adance for your replies.

 

[gas4you]

Check your cyl stat is wired correctly. Usually it is the 3 port valve head, sometimes the body. Take the head off and check for movement in the spindle. if you can feel hot water going each way with you turning spindle then change the head.

Simple job if you follow previous wires. Dont take all wires out at once unless you write down where they come from first

All this assumes that you have a modern valve that the head can be changed on

 

[fitz4x4]

Thanks for that reply.
I should have said the system has been working perfectly for years until I ajusted the cylinder stat.

The question was if the cylinder stat is knackered can this fault on it's own make hot water go to the rads (HW only selected on programmer)

 

[ChrisR]

No.

But systems which are described as "Working Perfectly for years" often have installation and wiring faults which means they can't have been.