TRV/Control Valve wont close...

[neds]

Had to remove a radiator and closed the lockshield vale and turned the control valve off. Well thats what I though I did! Took the rad off and perfect no drips from either valve. The lockshield valve doesn't drip at all its the friggin Control valve that seems to open and close when it feels like! I took another one off another rad and its even worse. I can only assume they are knackered?

Then I thought It could be a TRV however my control valves are over 20 years old so I can only assume they are not? Anyway since they are this old and I doubt there are any caps that I can buy for this particular control valve I was thinking of a way to stop the valve from letting all the water out as I need the rad off for at least a day while I tile behind it.

Can someone confirm that the valve is closed when the pin is pushed in? If so Could I possibly add something to the end of the pin thus when the control valve cover is put back on it exerts a greater force and permanently locks the valve shut until I remove it.

I really want to avoid draining the CH to that level as there are 7 rads above it!

Or any other ideas most welcome.

Cheers!

 

[seco services]

stick 5p in the top then close it.
or a blanking cap on the end of the valve.

 

[neds]

Hmm Cheers! in a moment of panic I just stuck the rad back on as I had nothing to hand to stop the leak!

I'll try the 5p trick or find an end cap nut like that. What size nut would that be?

I'm only a few months into my plumbing course and they don't teach things like this!

Cheers

Edit: Just checked seem the nut attaching the Control valve is bigger than say a regular 1/2" Possibly a 22mm end cap will fit...

 

[swbjackson]

If it's not 1/2" it's most likely 3/4" . Get yourself a selection of both sizes.

Mike