Copper pipe and rad ends

[Carlnorwich]

I am about to move a radiator. I've got the 15mm copper pipe and the 'push fit' elbow/straight attachments, it's how I attach the pipe to the radiator ends thats puzzling me.

I'll use the thermastatic valve again and I'm looking at it now. The copper pipe goes up into the valve and is secured by a large nut. But how does it hold the pipe securely/watertight?

There must be something clever going on under that large nut that stops it leaking? Whatever the answer is, it must be the same at the other end of the rad? (as the same thing is happening).

I hope this makes sense.

 

[Redhotferrari]

Brass olive which clamps onto pipe when nut is tightened

 

[TicklyT]

Sounds like you are looking at a compression fitting.

There is an 'olive' (a soft brass or copper ring) that slips over the pipe between the nut and the fitting.

There are two conical faces, one in the fitting, and one in the nut. When the nut is tightened, these faces compress the olive, which grips the pipe, and seals the joint.

if the pipe, olive and fitting are all clean, in good condition and tightened correctly they usually seal well. Some prefer to add a bit of PTFE tape or jointing compound as 'belt and braces'. IMO it's usually unnecessary unless you are re-making old joints.

Once compressed, there is little chance of removing an olive from a pipe and re-using it.

Replacement olives are available from plumbers merchants and DIY sheds.

 

[Carlnorwich]

Excellent - thanks very much.