Diagnosing damp patch under radiator?

[kissinger]

I noticed a patch of damp 50cm in diameter around the pipe to the left of my living room radiator this morning. What could the cause of that be? (I’d rather try and fix it myself before calling out a plumber.)

 

[Mr Chibs]

Post a pic, could be the rad, the pipes...

does there look to be any corrosion on the rad? Or near the plugs/valves?

 

[kissinger]

Post a pic, could be the rad, the pipes...

does there look to be any corrosion on the rad? Or near the plugs/valves?

I can't see any signs of corrosion. However I think I've found the source of the leak. You can see a water drop coming out of the bit where the radiator connects to the pipework. There some water around the connection on the vertical pipe as well, but that could be leaking from above:

 

[kissinger]

Actually I think the leak is coming from the top of the thermostatic value and dripping down, as you can see here:

 

[terryplumb]

Yes it is leaking from the valve. Show us a pic of the valve in full . Can you remove the plastic valve head ,it doesn't look like a thermostatic valve . You maybe able to fix the leak ,failing that it's a new valve required.

 

[kissinger]

Thanks. I took the cover off. It is a thermostatic value, just a very old one. There was a load of green funk, which I cleaned and then I tightened the top nut. That seems to have fixed it.

 

[45yearsagasman]

Certainly doesn't look like any TRV I've ever seen.

 

[terryplumb]

Certainly doesn't look like any TRV I've ever seen.

Nor me !!

 

[oldbuffer]

1. Its not a thermostatic valve, not that it matters.
2. Try tightening:
2a. The nut attaching the valve to the radiator tail. Spanner on nut, handle vertical, push the handle towards the wall. While tightening hold the body of the valve with another spanner to stop pressure on the pipework.
2b. The nut attaching the valve to the pipework. Spanner on nut, handle horizontal to the left, pull handle away from the wall.