On Fri, 12 Mar 2021 11:20:12 +0000, John Rumm wrote:

On 12/03/2021 10:37, George Miles wrote:

38mm or 40mm or 43mm,
do I measure the inside or the outside of the pipe?

Its typically the outside diameter that needs to match.

And 40mm solvent pipe is different size than 40mm pushfit pipe !

Yup, by design, so you don't try a solvent weld pushfit pipe (wrong type
of plastic)

aaaarrrggghhhh

Indeed... I keep a stock of both, and a few "universal" compression
fittings so you can transition from one to the other.

I realised, too late for that job, to use solvent weld in "universal"
fittings. It's resistant to UV (push-fit is PP and isn't resistant) and the
solvent-weld pipe, being the bigger OD, is a tighter fit in compression
fittings.
The comp. system on the washing machine has gone a bit slack - still OK but
won't tighten any more.
--
Peter.
The gods will stay away
whilst religions hold sway