Hi,

My father-in-law recently helped me to remove a couple of radiators to
allow easy access for decorating. I had shut off the valves and drained
the system but we then just lifted the radiator off, with the valve
still attached (I didn't refill the system until I'd done the
decorating). After having put them back on both of them have slight
leaks from the lockshield valves. Water is leaking from under the metal
cap. When I take the cap off I can see the water coming up past the pin
that is used for balancing the flow.

On one of the radiators it's more of a weep than a leak but the other
one is worse. In fact, when screwing down fully the pin under the metal
cap the water gushes out - I thought this was supposed to shut off the
flow of water to the radiator (system full when I did this - could I be
seeing water coming back from the radiator)?

The radiators are probably about 20 years old - have I possibly
disturbed some gunk which was stopping the leaks before? The valves have
two pipes at the same end of the radiator and a plastic pipe that runs
along inside the radiator (Yorkshire Imperial). Picture he
http://tinyurl.com/apg3e

As you can probably tell my plumbing knowledge is minimal so I could use
some advice! Is there something I can try tightening, or do I need to
replace the valve? The cap on the lockshield valve has rubber on the
underside - does that mean that water coming up past the lockshield
pin is expected?

Cheers,
Grant

I can see the water coming up past the pin that is used for balancing the flow.

Quite usual. The seal is by means of a 'stuffing gland'. The stuffing
is a fibrous material which is compressed around the pin/shaft.
Adjusting closing any old valve is likely to cause a leak from the
stuffing gland.

There should be a nut around the pin/shaft. Tightening the nut slightly
will compress the stuffing around the shaft and hopefully seal it. If
it's too tight, you won't be able to turn the shaft.

If it doesn't seal, you can add rolled up PTFE tape to the top of the
stuffing. The stuffing material contained asbestos fibres up to about
1992, so I wouldn't try removing it. Just buy a new valve if it's too
bad or the shaft is scored.

Aidan wrote:
I can see the water coming up past the pin that is used for balancing the flow.


Quite usual. The seal is by means of a 'stuffing gland'. The stuffing
is a fibrous material which is compressed around the pin/shaft.
Adjusting closing any old valve is likely to cause a leak from the
stuffing gland.

There should be a nut around the pin/shaft. Tightening the nut slightly
will compress the stuffing around the shaft and hopefully seal it. If
it's too tight, you won't be able to turn the shaft.

If it doesn't seal, you can add rolled up PTFE tape to the top of the
stuffing. The stuffing material contained asbestos fibres up to about
1992, so I wouldn't try removing it. Just buy a new valve if it's too
bad or the shaft is scored.


Thanks for your reply - very informative. There is a nut round the pin
which I tightened slightly but unfortunately it made no difference.
Unfortunately I have now noticed rusty-coloured weeping from the body of
the valves on both radiators so I can only assume that they are corroded
and will need replacing anyway.

Cheers,
Grant