leaking radiator!

moneypitt

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Moved into this house a few months ago, and now figured out that the stain in the living room ceiling is due to a leak in the radiator plumbing in the master bedroom right above it.

On investigation, it looks like the open/close valve (white plastic cap thingee close to the floor, at one end of the radiator) is leaking - and its leaking only when if I turn on the flow into the radiator. If I close the valve completely, leak stops in half hour or so. Needless to say the room is freezing cold last few nights!

Any idea if this is a minor fix and how to go about it?

Thanks for reading!
 
Because the valve closes when you close it, the valve should be ok and it sounds to me like the nut tightening the valve on to the radiator is loose or leaking. If it's old it may due to rust, if new then it was probably never tightened properly/sealed. If new - You could try just tightening it very slightly, if their is no "give" then don't take any - i.e don't force it and support the valve while turning the spanner.

Next option, close this valve and the valve on the other side of the rad. This other valve is a 'check' valve and limts the flow through the rad. It is inportant when you close it that you count the number of turns and when you open it again that you open it by the same number of turns.
With both valves closed, get a bucket for water and unscrew one USE THE NUT ON THE RAD -- NOT THE PIPE. You should now be draining the rad. When empty you will be able to clean the threads and apply PTFE tape. Reattach the valve to the rad and open both. Check for air after a few minutes using a rad key.

If both of those don't work then the next step involves draining down the system and replacing the rad valve, which is where I myself would call a plumber because I can't do compression joints (never seen it done.)
 
Thanks a million, Owenm!

The house is approx 10 years old. Had another good look and figured out that its the valve thats leaking. Its not leaking from either end of the T connector / joints - nuts/thread/joint to both the pipe and the radiator is dry. And as long as the valve is fully closed, there is no leak, but if I open the valve even a thread or two, it starts leaking and its coming from right under that white plastic cap.

From what you said earlier, this looks more like replacing the radiator valve, or something in the valve, either way its something do with 'compression joints' and so its better to call a plumber?

Thanks again!
 
moneypitt said:
Thanks a million, Owenm!

The house is approx 10 years old. Had another good look and figured out that its the valve thats leaking. Its not leaking from either end of the T connector / joints - nuts/thread/joint to both the pipe and the radiator is dry. And as long as the valve is fully closed, there is no leak, but if I open the valve even a thread or two, it starts leaking and its coming from right under that white plastic cap.

From what you said earlier, this looks more like replacing the radiator valve, or something in the valve, either way its something do with 'compression joints' and so its better to call a plumber?

Thanks again!

Remove the white cap from the radiator valve and tighten the nut at the top just a little DO NOT FORCE IT if you cannot tighten it then yes you will need a new radiator valve if you can tighten it then this should solve your drippy leak. A new radiator valve is not expensive and a good plumber should only take a half hour to fit it so it shouldn't cost you much.
Good Luck ;)

http://www.diynot.com/pages/pl/pl053.php
 
Compression joints are pretty straightforward. Wrap a couple of layers of ptfe tape on the thread, hand tighten the nut againts the olive, then with two spanners, turn a further full turn to form the joint. Practice on a piece of scrap pipe, it'll only cost you the price of a few olives.
Leo
 
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