Another leakt Header tank

[bryntheblade]

HI all,
In our loft, the small tank (header??) has a constant drip. The bit where water comes in has a drip, resulting in the overflow constantly dripping. Do I need to replace the arm and ball valve to stop it? Also, where does water in there come from? The heating isn't on.
I hope this is enough info.???
Thanks

EDIT
If I lift the ball cock, it still drips.

 

[denso13]

Try a washer first. Is it a brass valve? http://www.youtube.com/watch?v=eKoeHtICzvM&feature=related. Their should always be water in the cistern which keeps your heating system topped up.

 

[JohnD]

it is very cheap, but quicker and less effort, to swap the old ballcock for a new one.

If you feel like it, you can repair the old one at your leisure, and put it in a plastic bag next to the tank ready to swap back next time it happens.

The new one will usually fit onto the old threaded stem that is fixed to the tank, if you undo the big nut. When you have the new one in your hand you will see what I mean.

 

[bryntheblade]

It is a brass one. I think I will have a go at swapping the ball cock bit over.
Cheers