Sealing radiator leak?

[Steve]

We have a new radiator in our new kitchen, but its leaking where a valve screws into it. Can I use PTFE tape on the threads. or is there something more suitable? Thanks.

[Andy Hall]

That's fine/

Make sure that you wrap 6-10 turns of tape onto the thread and in the correct direction. This should be so that the free end of the tape "points" anticlockwise as you look at the radiator. Then as you screw in the fitting, the tape will tend to tighten.

Don't forget to add inhibitor when you refill the system.....

.andy

To email, substitute .nospam with .gl

[PoP]

Are you sure the valve has been fully tightened onto the radiator? Might be worth putting a spanner on it to see if it can be tightened slightly (remember to use another spanner on the other side of the joint to counteract the tightening pressure - you wouldn't want to yank the valve off the pipework!).

PoP

[Colin M]

The threaded section where the valve attaches to the radiator uses the conical face of the mating surfaces to seal, not the thread. Adding PTFE to the thread won't help much.

Best to open it up and smear a bit of Boss White on the face of the joint and retighten.

Colin M

[Andy Hall]

I think that you are confusing two things here, Colin.

The threaded connection, which is the problem the OP describes, if leaking, would benefit from being re-done with PTFE tape.

The conical joint between the tail and the valve *should* seal on a metal to metal contact if it is clean . Sometimes they don't and no matter how much they are tightened there can be a tiny seepage. In this case, some sealant such as Boss White or a specific PTFE liquid sealant usually does the trick.

.andy

To email, substitute .nospam with .gl

[Colin M]

Andy

I assumed because the OP wrote "radiator ... it's leaking where a valve screws into it" that he meant the valve to rad coupling which relies on the mating surfaces rather than the pipe to valve which relies on an olive. The only joint I found PTFE tape helps seal is the threaded section into the rad itself.

Colin M Reply to group, or if email required, replace the abuse with broxie

[Andy Hall]

Agreed. Definitely PTFE tape is not useful for the valve to tail joint, and I realised that that was what you meant.

.andy

To email, substitute .nospam with .gl

[NJF]

Depends on the rad, one of the guys here got some cast rads that have parallel threads and PTFE was useless, ended up using locktite 577.

Niel.

[NJF]

Depends on the rad, one of the guys here got some cast rads that have parallel threads and PTFE was useless, ended up using locktite 577.

Niel.

[Roger Mills]

PTFE tape is fine - but it should already have some on it! You will have to drain the radiator to fit (more) tape - but you needn't drain the whole system - just turn off both valves on that particular rad - and then undo one of the unions between the 2 halves of one of the valves to drain it (protecting the flooring from any 'orrible black sludge you may spill in the process!) It helps to loosen the bleed screw too, to let some air in at the top as the water runs out at the bottom.

The radiator tail (the bit which screws into the rad) just may have an external square on it - in which case you could try tightening it with a spanner rather than draining and dismantling it. [It it doesn't have a square - and not many do - you will have to take it apart in order to tighten it with an internal allen key].

Roger

[Steve]

Yes thats what I meant.

Thanks to all for your help.

[Steve]

Cheers Roger. I think I needed a bit of advice about taking it all apart. Its a brand new radiator, fitted by the buiilder who did our building mods and fitted the new kitchen. Having got his money, we haven't seen him since, and the radiator is just one of several unfinished or bodged jobs we have found.