novice plumbing question, kitchen sink waste

plumbdog

[Replacing the kitchen waste myself as much for education as money-saving, only intended as a temporary job with a flexible P-trap as there is a shelf under the sink that will be coming out but which at the moment has just not enough depth for a rigid waste pipe.]


I bought a 40mm flexible waste pipe with a compression fitting for the sink connection & (separately) a pushfit straight connector for the waste pipe - both sold as 40mm compatible - the pipe is too small for the connector.



The pipe diameter actually is 40mm, the connector is 41mm marked 38, but it does seems as though that would be the right fit for the existing waste pipe which is also over 40mm, & being older I expected more trouble from that, than 2 new components that you'd expect to be standard.. What should they actually measure if sold as 40mm, given the whole "Please Note: the 32mm and 40mm measurements are a general size referred to in the plumbing industry, they are actually 31.75mm (1 1/4") and 38.1mm (1 1/2")" thing? Where does 38mm actually come into it if nothing I have measures 38? Thanks if some kind soul can help, I have googled, without much success (eg https://www.diydoctor.org.uk/forums/waste-fittings-dimension-dementia-t7472.html) - none the wiser frankly. :huh:

-taff

Did you buy them in different places? I've found it easier to buy the same make in the same place for plumbing jobs.

plumbdog

Hi, thanks, yes they were different places/makes, admittedly probably not the best plan.



What I'm curious about is whether it's the flexible pipe that is technically too small at 40mm, or the connector too big. Even then, if the connector fits the waste outlet pipe but not the end of the new flexible pipe, then it looks like any connector wouldn't be right for both, so I'm up the creek either way it seems.

Ruski

Compression fittings will fit both solvent waste pipe (bigger diameter) and pushfit pipe (smaller diameter) - both are described as 40mm.

So get a compression coupling and all should be good.

HTH

Russ

plumbdog

Thanks, I can see that's the logical approach to skirting round the sizing vagaries, I have ordered a compression connector & will (hopefully) proceed from there. Cheers.



Lesson learned that, as so often, should fit does not necessarily = will fit..

Ruski

plumbdog wrote: »

Cheers.

Lesson learned that, as so often, should fit does not necessarily = will fit..

Don't beat yourself up about it, it's only a thing most learn from experience.. in mine - 15 years experience of customer's bodges

Russ