Heating coming on for no reason.

[dmills27]

Hi,
I have a problem with my heating, and as the people on this forum are very helpful I was hoping that you could help me again. Firstly a few weeks ago my heating pump went, I got this replaced (£65 including pump, fitting and VAT which I though was quite reasonable) anyway now the heating is coming on for no reason; the thermostat is off as well as the controller yet the heating still on. After reading other threads It seems like it could be the motorised valve. Firstly:

1. Could there be any other reasons why this is happening?
2. If not then what can I check? I can take the electronic actuator off no problem but am right in thinking the problem could be the valve itself? If so how can I check that this is ok? I am hoping to rule everything out except the actuator which I can replace myself.

The house is five years old and I do not have a combination boiler.

Thanks a lot

 

[bathjobby]

If your room thermostat is off the only other thing that calls the boiler for heat is your hot water thermostat. So I would guess your H/W therm is calling the boiler and your valve is stuck partly open putting heat into your rads. The natural resting position for the valve is hot water, when the room stat activates, the motorised valve drives the valve either to mid pos (hw and heating) or full position (heating). When off I believe the valve returns to the H/W position by a spring. So when the heating isn't working its usually the motor that is duff, but in your situation probably the valve stuck or the spring. Can you manipulate the valve position using the lever on the side of the actuator ?

 

[dmills27]

I will try when I get home to see if I can move this. I took the actuator off last night and tried to move the valve spindle by hand it did move but should it rest in a central position and turn both right and left?

Also on top of the actuator there is a black plastic part which I thought was some sort of switch but thinking about it now is this an indicator saying what setting the valve is currently in?

Thanks!

 

[Slugbabydotcom]

(£65 including pump, fitting and VAT which I though was quite reasonable)

Too cheap if you ask me. The guy either did you a real favour or he stole the pump

 

[bathjobby]

They normally go from resting possition (h/w only) through the mid position (h/w and c/h) through to full position (c/h only). You may also be seeing a micro switch in the actuator housing as when going to c/h only the boiler looks for a signal back from a micro switch telling it the valve has reached this position. If it doesn't get that signal after a few seconds it will switch itself off for safety.

 

[ELZ4742]

yep, sounds as though the 3 port valve has had it,remove and test the orange cable, if its permantly on chances are the actuator is bugered.
or quite possibly if it has one the frost protection has cut in, wheres the boiler situated?

 

[dmills27]

Thanks,
Double checked the valve last night and I can move the spindle freely by hand - think I will fit a new actuator myself and if that fails get the plumber back - thanks for your help!