TIGHTENING RAD NUT

[Steve Barnes]

Having just removed and replaced a radiator for decorating the valve at the return end that fits onto the actual pipe seems to have quite a lot of movement when tightening the nut fitting to the radiator (please excuse my lack of plumbing terminology). This nut is not yet fully tightened and I'm afraid in doing so would cause the joint at the pipe to leak. Firstly, is there a more effective way of while tightening the radiator nut to hold the pipe nut other than to put a spanner to it, this doesn't seem to hold it rigid very well. Secondly, if a leak did appear at the pipe end what would I need to do to fix it, is it a compression fixture, could a new valve just be fitted to the end of the existing pipe or does it need to be cut back and a new length of pipe fitted? Your help would be greatly appreciated.

[Christian McArdle]

The compression joint between the valve and the CH pipe just needs nipping up a bit.

Christian.

[Set Square]

Let's sort the terminology first.

The valve is in 2 parts - the body which is attached to the flow or return pipe with a compression joint, and the tail which screws into the radiator. The 2 parts are connected together with a conical fitting - and this is what you undo when you remove a rad for painting - leaving the tail in the rad and the body on the pipe.

Tightening the cone joint shouldn't take a lot of force. I usually smear a bit of Boss White on the mating surfaces, which helps it line up and seal better. If the body has a tendancy to rock on its pipe as you tighten the joint, take the knob off and hold the body *lightly* from above with a Mole Wrench, using a bit of rag in the jaws to protect the chrome. [Make sure you grip the body and not the spindle. The spindle should sit safely inside the hollow bits of the Mole Wrench].

Once the body is firmly re-attached to the tail, you can tighten the compression nut on the pipe a little if it needs it.