Justin wrote:

I see so you use different inserts if using compression joints on plastic
pipes?


Well, yes and no :-)

Each manufacturer has their own inserts. SpeedFit make plastic inserts
with an O ring on the end - so you get a double O ring seal. Hep make SS
inserts. Cuprofit make copper inserts.

The purpose of the insert is to prevent the pipe from
bending/collapsing. It doesn't really matter which you use - they all do
the same job. If using speedfit fittings, I usually use their plastic
inserts with the extra O ring. But I have (and do) use the inserts
interchangeably.

The plastic inserts have a thicker wall than the copper ones, and so
will cause a greater restriction. The stainless ones have the thinnest
walls of all. So if I were you, I'd use stainless inserts throughout,
thereby achieving minimum restriction.

--
Grunff