Mid position valve problem

[shaggie16]

Hi, can anyone help?
I hve recently had to drain the system completely, twice, to have a radiator replaced, but I'm hoping this is incidental to the problem.

Gledhill thermal store - but that's irrelevant really. Hot water is fine (valve in the non-actuated position.) Central heating only gives a tiny amount of warmth on the rads (not hot at all) even though the store is well up to temp.

If I put light pressure on the lever on the valve acuator, even when the heating is called, it has not moved very much at all. If I manually push the lever to the central position, the rads get piping hot. The room stat is satisfied, the valve actuator returns under spring pressure, but when the room stat calls again, the same problem occurs.

The valve body (not the actuator) was changed earlier this year. I have taken the actuator off, and the valve spindle is easily and smoothly rotated with finger, so I assumed the actuator was duff. However, with the actuator NOT on the valve body, the actuator operates exactly as it should! This confuses me, as I say, the valve spindle itself on the body of the valve can be rotated with light finger pressure....

Is it possible for an actuator to become weak or am I barking up the wrong tree?

Thanks in advance,

-m.

 

[jonnyswamp]

Replace the synchron motor if you can, it's gone a bit like me.....lazy

 

[shaggie16]

Thanks - when you say replace the motor - do I just replace the entire actuator, or is the motor available seperately?

 

[jonnyswamp]

Depends on manu, should be able to change the most common makes
Or, if the heads are removable, change the whole thing would be a better option

 

[shaggie16]

Thanks for the replies. It's 32 quid for the entire actuator so makes sense just to do that. This one has been in service since 2000 so it doesn't owe me anything. Thanks again.

 

[buckley plumb]

I change the complete valve now less call backs. Are you sure the room stat is giving a voltage to the zone valve to move it

 

[shaggie16]

Haven't checked voltages, but the motorised part of the valve moves when it is removed from the valve spindle, so I would say yes. Will just replace the actuator then as the valve was replaced a few months ago, but the original actuator was reused. Thanks

 

[buckley plumb]

Is the spindle easy to move if not replace complete assy.

 

[shaggie16]

Yep, spindle easy and smooth to move.