Radiator Valves

[Ginty]

Hi,

Quick question...

I've never fitted a radiator valve until now and so just want to get the basics right. It comes in two parts. With the first part, containing the threaded connection to the radiator, I've wrapped in PTFE tape and connected securely to the rad with a radiator spanner. The other part containing the valve itself, has a concave connection that mates with the rounded end of part 1 and is secured by tightening a nut.

Now my question is should I apply any kind of sealant or anything to this joint or is the shape of it inherently watertight?

Hopefully this makes sense. Don't want to sound dumb but chances are I'd look even dumber if 10 rads start leaking when I fill it up!

Thanks for your help.

Cheers, Stephen

[Roger Mills]

In theory, it doesn't need anything and the two mating conical surfaces should seal ok. However, being a belt and braces man, I always put a smear of Boss White on the mating surfaces.

Roger

[Andy Hall]

This kind of joint is called a union, and like all unions it's kind of OK in principle but in practice can be less than perfect.

A good quality one should mate together and not leak or even drip once tightened.

I tend to put a light smear of a PTFE sealant such as Screwfix 12693 on the mating parts and never have any issues. Without this, I have occasionally had slight seepage which can usually be fixed with more tightening - I just prefer to use the sealant approach

.andy

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[John Laird]

You have one vote for Boss White, one for a Screwfix sealant. I'll add one for Fernox LS (I've just had to toss out the remains of the tube I bought some 12 years ago as it had finally started to dry up).

The joint is not supposed to need anything, but I don't think either side is sufficiently soft to take up any manufacturing irregularities or make a soft weld (unlike the olive and copper used in compression fittings). I usually wind a bit of PTFE tape around the thread just to stop it making horrible creaking and binding noises too.

[Andrew Gabriel]

I'll add another vote for nothing at all. I never use anything on ball and cone type union joints and I haven't had one leak. The trouble with introducing something comes later if you need to disassemble and remake the join. If the substance has gone hard or attracted any dust or grit, it will defeat the operation of the ball and cone seal by either displacing them or damaging the mating surfaces, and it will then leak.

[Ginty]

Thanks all for your info, its certainly put my mind at rest - I appreciate it. I've done most of them already anyway, with nothing at all, so I'll try it at that and see how I get on. Cheers for the tips though if I run into problems.

Stephen

[Ginty]

Thanks all for your info, its certainly put my mind at rest - I appreciate it. I've done most of them already anyway, with nothing at all, so I'll try it at that and see how I get on. Cheers for the tips though if I run into problems.

Stephen

[Nick Finnigan]

Not a direct answer, but I recently bought some replacement non-TRV 10mm radiator valves from BanQ which came with PTFE tape already on the first part, and a rubber insert for the ball and cone connection. Just add spanners.