Radiator problem

[Grant Fitzgerald]

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 here:

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

[Aidan]

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.

[Grant Fitzgerald]

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