On Aug 29, 8:41*pm, "AL_n" wrote:
The header tank atop my immersion heater has a brass float-operated valve..
It started leaking last year, allowing water to leak out of the overflow
pipe. I took the valve apart and found that the seal is formed by a small
rubber disc, about 8mm diameter. It had become a bit worn on the *side that
mates with the moving piston. So I simply reversed the rubber disc so that
the nice, flat pristine side was on the side that touched the moving
piston. All was well, or so I thought.... Now it is leaking again!

Should I now replace the whole valve, or can a new rubber disc be obtained
from somewhere?

These brass valves have been around since time immemorial, and they aren't
exactly cheap. Is there anything available nowadays that is cheaper and
more reliable? Can anyone provide a link to a valve you can recommend?

TIA...

Al
Thisis a virtually indestructible device that can be maintained
forever.
All you need is a new "disc" (ballcock washer is the correct term.)
Any DIY store will have them.
You need to examine the face of the conical jet it bears against, may
be brass or plastic but needs to b e perfectly smooth. Clean/smooth
with fine wire wool.

Also check it has not split ,as occasionally happens. (Frost damage).

BTW, you are aware the brass "slug" containing the washer comes apart
by unscrewing?