Radiator Valve Leaking - PTFE?

[Damian30]

Hi,

Thanks to my 1 year old deciding to pull the radiator off the wall, I need to remove and refit one of our radiators yesterday.

However, I have noticed that there is a slight leak coming from the union between valve connector (the fitting screwed into the radiator with PTFE) and the actual valve.

When I read up on how to do this connection, the use of PTFE or jointing compound wasn't suggested and it just suggested as tight as necessary. I will re-drain and re-connect but should I be using PTFE or something?

Also, I was trying to use some adjustable pliers to grip the valve whilst tightening but they were pretty useless and I couldn't get a good grip. Is using a pipe wrench/stilsons better for holding the valve body tight in these situations?

Any help much appreciated.

Many thanks,

Damian[/img]

 

[fatplumber]

A valve joins the tail with a union. The sealing surfaces of a union are not the threads. If you look at the unions, you will see how they fit together. te mating surfaces will be better for some jointing paste, boss white, hawk white etc.. PTFE tape isn't really going to do it. Water pump pliers, small stilsons, adjustable spanner anything that holds it will do.

 

[Damian30]

Hi,

Thanks for the reply.

I don't fully understand all the details of the fittings involved but doesn't the union (and the permanently fixed olive looking sealing ring) work a bit like an olive by putting some compression between the tail and the valve to create the seal? I guess I am not clear on how the seal is created between the tail and the valve.

Is there a preferred product of those you mentioned - I guess you just smear the stuff over the part of tail where the are making the fitting.

Thanks for the help and sorry for the additional questions - just useful to learn this information for future reference.

Thanks,

Damian

 

[Damian30]

Hi,

Thanks for the reply.

I don't fully understand all the details of the fittings involved but doesn't the union (and the permanently fixed olive looking sealing ring) work a bit like an olive by putting some compression between the tail and the valve to create the seal? I guess I am not clear on how the seal is created between the tail and the valve.

Is there a preferred product of those you mentioned - I guess you just smear the stuff over the part of tail where the are making the fitting.

Thanks for the help and sorry for the additional questions - just useful to learn this information for future reference.

Thanks,

Damian

 

[bengasman]

To keep things simple, the only time you use tape is on thread-to-thread seals like BSP, nowhere else.
Chances are that the pipe is damaged when the rad came off the wall, so you will have to cut a bit off, and replace the lot.

If the rad came off the wall by a 1-year old hanging on it, I would strongly recommend testing all the rads, or better, taking them off and re-mounting the brackets properly. The next time it happens could put the sprog in hospital, and guess who the missus will blame for it?
And she would be right.

 

[fatplumber]

the same rules apply to an olive. The mating surface is the curve of the olive and where it touches the valve. You can wrap a bit of PTFE round the olive. Not best practice but we all do it.

 

[JohnD]

PTFE on an olive seems to work, and is cleaner than paste, so is there anything wrong with using it?

BTW, Damian30, what is the wall made of, where the rad pulled off?

 

[bengasman]

Lots of people wrap teflon around olives, that doesn't make it right.
It will sometimes work as a stopgap measure on a faulty compression joint, but I think few people would argue that it is better to make a clean, correct compression joint in the first place in which case it does not need anything else to make it tight.
And let's face it, it is not that difficult.

 

[fatplumber]

Hey call me a cowboy but I often use ptfe on olives, even ones that were alreay leaking. It forms a good gasket. (Gasket. old plumbers word) I am an old fart who didn't even want to put a pump on central heating. God made convection for a reason, but I have at last ditched me boss white and hemp, except for special jobs.

 

[bengasman]

Hey call me a cowboy but I often use ptfe on olives, even ones that were alreay leaking. It forms a good gasket.

These are the cases where teflon can work if time/budget/access do not allow to cut out and rebuild.

If you have been in the trade that long, you can probably make joints on new pipe that will hold 30 bar without even trying.

 

[fatplumber]

Yep and we used to test caulked mains to 130psi for ten minutes. I'll still use PTFE on olives.

 

[Damian30]

Hi,

I think I understand the fittings a little better now - both union and compression fittings should make a tight fitting but need to be completely flush, clean, etc, and ideally shouldn't need any help. The union fitting allows for easier removal /re-fitting of the radiator, rather than a compression fitting which requires a little more work.

I have found some Boss White in the garage, is it worth me taking off the radiator cleaning up the unions and re-fitting with some Boss White applied (or a better product?)? Or do I have a few more goes at trying to get the fitting to work without any assistance?

John D - it is a small radiator on an internal plasterboard stud wall. Its a modern house so the builders used basic plugs rather than finding a stud or using better fixings. For now, I've put in some expanding metal fixings so you would pretty much have to rip the plasterboard off to get the radiator off now. However, when I get more time, I think there is a stud close by and I may adjust the brackets to at least get one bracket in the stud (obviously subject to me being confident in getting the radiator fittings to seal.

Thanks for all the replies so far.

Damian

 

[JohnD]

a useful tip on Plasterboard is to put a couple of horizontal wooden battens, or a slab of ply, on the wall so that each bridges at least two studs, and then screw the rad brackets to that. If necessary you can fix the ply or battens to the plasterboard itself with multiple fixings.

You can paint the battens to match the wall, or, if using ply, you can put wallpaper on it. As it is below the top of the rad it is not very visible.