Connection from new sink trap

[CountryFan]

So you're trying to go from solvent weld (white) into push fit grey, which could be 1.25". I think you can get solvent weld to push fit adapters but you could also use a universal elbow.

 

[Hugh Jaleak]

You're trying to connect two different systems, Solvent Weld and Push Fit, and as you've discovered, they're not compatible. Solvent Weld pipe and fittings should be standard across all the manufacturers, although some People have said the brand offered by Toolstation is slightly different size, enough to cause an issue. Push Fit has never been standard across the Manufacturers from memory.

Only way of joining the two is with a Compression Waste fitting, not ideal underfloor, although someone has already used a Compression fitting under there!

Remove the bend you are trying to connect to and replace that with a Compression Bend of the appropriate diameter, then I'd use a 45º Solvent Weld bend, and a short section of pipe to drop your new waste run into the Compression Bend on the existing pipework.

Having said all that, you may be better to look at the feasibility of replacing what is under the floor with Solvent Welded pipework. Done correctly it is guaranteed never to leak, my only concern would be where it is running to, you don't want to be disturbing old Boss connection's to a stack.

 

[ChrissyPy]

Thank you for all the replies, I'm getting close. I don't really want to start replacing the existing push fit under the floor however my next job is to remove the toilet to replace the subfloor so maybe I could try and tackle it when I have some more space.

1st photos shows the 43mm solvent weld that's ever so slightly to big.
2nd photo shows the 32mm that's to small.
3rd photo shows the 40x32mm reducer that I bought snugly fits in.
4th photo shows a solvent weld reducer on the 43mm elbow, with the 32mm pipe going down but it's ever so slightly to big to fit into the reducer that's installed into the existing coupler.

So I either need a compression fitting that goes from the 43mm into the existing pipework OR a compression fitting for the 32mm into the existing pipework. It makes sense to find one for the 43 otherwise I'm just adding extra sizes of new pipework and connections unnecessarily.

Is it possible someone could provide, a Screwfix link that shows the suitable compression fitting?

 

[ChrissyPy]

Looks like the photos got mixed up

 

[CountryFan]

Doesn’t matter so much about the photos, but the one that fits snuggly is a push fit x push fit, you need push fit to solvent weld or a compression elbow.

 

[ChrissyPy]

All sorted, just now need to get everything in its final position, marked and welded.

 

[ChrissyPy]

Thank you to everyone's comments, I was annoying myself so lord only knows what you lot are like, I managed to get rid of all the grey push fit that came from the main run just to minimise any later leaks. Everything is solvent welded ready to test later today.