Plumbing Question

Radiator replacement - best way to tighten olive joints?

Currently replacing some radiators due to springing small leaks. 8mm CH system, so 15mm (half-inch) valves with adaptors and olives.
I've heard that you should hand-tighten the joint over the olive, and then half-turn more with a spanner - correct?
Also, seems to be some dispute about whether to use PTFE tape on olive joints - or maybe jointing paste instead? What's the views folks?

Update 4th Jan 2012
Many thanks to all assistance, reinforces what I thought! Cheers, guys!

Update 8th Jan 2012
Well, took it all apart and reassembled using 10-12 turns of PTFE where applkicable, and jointing compound on compression joints - and it all works without a single leak!
Thanks to all for their invaluable assistance, I now know how to ensure leak-free raqdiator replacements for the future!

6 Answers

Best Answer

you should only use PTFE tape where the thread makes the seal

Answered 1st Jan 2012


Member since 20 Feb 2010

The tightening of the joint, as you have be suggested is correct.

In any event, do not over tighten ! !

I have been in the trade over 30 years and my ppinion of the use of P.T.F.E. over olive joints is :

It's a bit / D I Y ! !

Use Boss white / hawk white paste, for potabale water joint, or something similar !!!


Adrian Hagger

Answered 1st Jan 2012

Southsea Plumbing, Heating, Electrical & Gas Services

Member since 8 Nov 2010

use jointing paste

Answered 1st Jan 2012

Paul Caton Gas Services

Member since 23 Mar 2010

Hi Alan,

I would use hawk white joint compound on the actual olives and inside the radiator valve, check out you tube ( normally diy advice on there )

With the screwed tails going into the rad use the PTFE.

Many Thanks.

James Eastman
James Gas Services


Answered 2nd Jan 2012

James Plumbing And Heating Services Ltd.

Member since 2 Mar 2009

Hi,use ptfe tape on threads of fittings then tighten up finger tight, then tighten with shift spanner holding the other side with spanner or water pumps give them a good tighten, all should be good, best wishes colin.

Answered 31st Dec 2011

Rigsby Handyman

Member since 14 Aug 2009

Yes hand tight and half turn no need for ptfe and definitly no paste,if when you fill the system you have aslight weep on the nut just nip it a touch more.

Answered 1st Jan 2012


Member since 1 Jun 2008

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