Lockshield valve question

[razorkai]

Hi all.

I recently noticed a valve on one of our radiators leaking and having done a bit of research I have concluded it is the lockshield valve. I closed it right up and was expecting the radiator to cool down, but it seems to have no effect. I can turn it off completely using the valve at the other end, but from what I have read it is normal to open the lockshield valve slightly to balance the system. So my question is, is it correct for the radiator to still heat up with the valve closed?

TIA.

[Roger Mills]

No. Turning off *either* valve will stop water flowing through the radiator, so that it cools down.

If turning off this valve doesn't do this, the valve is shot, and isn't

*actually* turning off even though it appears to be.

[razorkai]

Hi Roger.

Thanks for the info. I found that the valve was leaking from where the spindle screws in - maybe it was unscrewed too far? When I screw the spindle in as far as it will go the valve doesn't leak, but as I said the radiator still heats up. Am I right in thinking that I should normally have the spindle slightly unscrewed as this opens the valve, and that if all is correct this shouldn't cause it to leak? Just to be sure on my terminology ( I am new to this), the spindle is a left hand threaded part that has two red o-rings on it and a square top?

Cheers.

[Roger Mills]

The spindle is a brass or chromed rod, about 6mm in diameter with a sqaure end - which is the bit you rotate to open and close the valve. It has a plate at the other end (inside the valve) which seals the external port when you screw it down, preventing any flow. There is a gland (probably O-rings in your case) at the point where the spindle comes out of the body, to prevent water from leaking out round the spindle. If the gland leaks, you may be able to fix it by replacing the O-rings. [On older types, you could undo the gland nut, wap some string around the spindle, and replace the gland nut - compressing the string round the spindle].

In normal operation, a lockshield valve needs to be open - somewhere between just open and fully open, to be determined when you balance the system. If your valve doesn't stop the flow when you screw it right down, it is shot anyway and needs to be replaced - so there's no point in fixing the gland because you'll get a new gland with the new valve.