"Roger Mills" wrote in message ...
I have gate-type isolator valves either side of my circulating pump. These
have recently started leaking slightly - not from the gland round the shaft,
but from the point where the gate mechanism screws into the body. They have
fibre washers which seem to have perished. Tightening helps a bit but there
is still a slight drip . . drip.

I intend to replace the valves - probably with ball rather than gate types
(any comments?). This will, of course, require the system to the partially
drained - so I need to wait for a convenient time - and need a short-term
solution.

In a recent post concerning a leaking joint on a radiator valve, someone
suggested using a silicon sealant. However, all the tubes of sealant which I
have got state that the surfaces must be clean and *dry*. There's no way I
can make my surfaces dry - until I fix the leak!

Does anyone have any suggestions of anything I can put on a damp surface,
which will still seal?

TIA,
Roger

Roger,

I had the integral 1/4 turn ball type pump valves to convert from 22mm
pipe to the pump flange. The first and only time they were used in
anger they promptly started leaking from around the ball handle. I
changed to the gate valve type of pump connectors.

My feeling is that these combination flange adaptors/valve are poor
quality and suffer from infrequent use. My preference would be a high
quality full bore ball valve (1/4 turn) and a separate adaptor flange.

ian