Can I apply PTFE to joint without draining whole CH system?

[tibi08]

I have a weeping compression joint on the motorised valve for my pressurised central heating system. I tried tightening the nut, to no avail.

I need to undo the compression joint, apply PTFE tape, and then tighten the joint again - HOWEVER, I would rather not drain the whole central heating system just to do this.

Can anyone advise if I could half-undo the joint, apply tape, and tighten - or do I risk flooding my house?

Untitled

• tibi08
• 27 Sep 2011
• 1

 

[misterdubya]

The olive makes the joint watertight, so no you cannot.

Bung the system, undo the nut and re-make the joint properly.

Mr. W.

 

[JimLoskot]

you could have a go but i think you'll find the more you unscrew, the more water comes out and you could also misjudge where the end of the thread is causing the pipe to come out and flooding your house.
Best to drain down the system and take the fitting apart as the fitting and or olive might be defective.

 

[DeltaT2]

This is a common problem caused by people not using Boss White(generic term) on compression joints. A practise that was employed by everyone, until the knowitalls stopped using it. These joints are now termed 'as dry joints' - which leak!!

I think you may need to drain the system, as you need to ensure the olive is not overtightened

 

[oilhead]

The olive makes the joint watertight, so no you cannot.

Bung the system, undo the nut and re-make the joint properly.

Mr. W.

Pressurised system, so relieve pressure, screw down any AAV's & you will have plenty of time to tape or seal the olive without major leaks.

 

[doitall]

This is a common problem caused by people not using Boss White(generic term) on compression joints. A practise that was employed by everyone, until the knowitalls stopped using it. These joints are now termed 'as dry joints' - which leak!!

I think you may need to drain the system, as you need to ensure the olive is not overtightened

How very true

 

[longdogs]

If you do attempt to undo it without draining, get a helper to keep the joint pushed together while you undo the nut

 

[Youllneverguess]

Wonder what lucky barsteward gets that job?

 

[misterdubya]

The olive makes the joint watertight, so no you cannot.

Bung the system, undo the nut and re-make the joint properly.

Mr. W.

Pressurised system, so relieve pressure, screw down any AAV's & you will have plenty of time to tape or seal the olive without major leaks.

Must have skipped that bit.

 

[muggles]

If you do attempt to undo it without draining, get a helper to keep the joint pushed together while you undo the nut

And get someone else to video it, then post it on YouTube so we can all have a giggle...

Seriously though, you're best to drain down and do it properly, the PTFE or jointing paste, whichever you choose to use, goes on the olive not on the threads