ron82
02-19-2010, 10:06 AM
Hi there,i have i big doubt regarding compression joints.
I have noticed that without puting any extra staff when making the joint (ex. joint compound or PTFE) sometimes when over tight they leak.
I've done many experiments my self:
-Sometimes even if they are tight up to the end of the thread,with cold water they can outstand a pressure of 10 bar. But when hot water (80 degres) flows through the joint i have a leak.
At this point i've tried to put a couple of turns of PTFE around the olive in the same joint,and it doesn't leak.
Everything it's quite clear,it leaks whith hot water due to the thermal expanction of the copper.
What i don't understand is,what happen to the olive when the joint is over thight?
The olive is crushed,i know this,but is still touching the conicol seating.
So is it leaking because there isn't enough pressure between the olive and the conicol seating caused by the compression of the nut pushing and crushing the olive inside the pipe?
If anybody have a proper answer.... Thanks
I have noticed that without puting any extra staff when making the joint (ex. joint compound or PTFE) sometimes when over tight they leak.
I've done many experiments my self:
-Sometimes even if they are tight up to the end of the thread,with cold water they can outstand a pressure of 10 bar. But when hot water (80 degres) flows through the joint i have a leak.
At this point i've tried to put a couple of turns of PTFE around the olive in the same joint,and it doesn't leak.
Everything it's quite clear,it leaks whith hot water due to the thermal expanction of the copper.
What i don't understand is,what happen to the olive when the joint is over thight?
The olive is crushed,i know this,but is still touching the conicol seating.
So is it leaking because there isn't enough pressure between the olive and the conicol seating caused by the compression of the nut pushing and crushing the olive inside the pipe?
If anybody have a proper answer.... Thanks