Isolation Valve Leaks

[Graham81]

Can flat blade screwdriver isolation valves be prevented from leaking from around the valve itself, say by using such a product as Fernox Leak Sealer?

I know this may well be a bodge, but they are on a boiler and a pain to change.

 

[Slugbabydotcom]

Probably but there is only one way to find out for sure.
Expect it to leak if you have to operate the valve afterwards

 

[Paul Barker]

We have learned not to use boiler isolating valves unless brand new, and also avoid using the built in red button drain off. We drain down below the boiler with the drain off at bottom of pipework if one was fitted which many times they aren't, or at a rad if not. Empty the rad, put a 3/4 female iron to 15mm con on the rad valce 15mm pipe, hose.

Just so you know for next time.