DIY Doctor UK DIY Forums

I have just fitted the Yorkshire fitting collar of a 25mm to 15mm stop tap onto my new water main MDPE 25mm pipe, slipped th e25mm olive over the pipe with it and had to ram in the black plastic insert into the end of the MDPE pipe. It is so tight now that it is impossible to turn the collar to make the connection to the stop tap!

Does anyone have any ideas what I am doing wrong?

Unless one uses the pipe inserts, I assume the olive will just chew up the MDPE pipe, but with them in it is impossible to make a connection.

Have you used the right insert for the pipe you are using ?

Though nominally the same outside diameter, the wall thickness of plastic pipe can vary by a fraction of a millimetre from manufacturer to manufacturer. Hence the inside diameters can be up to half a millimeter different.

Thus if you use an insert for a pipe with a thinner wall it is going to jam tight in a pipe with a thicker wall.

This can also occur with pex plastic pipe for internal plumbing where for instance Speedfit uses a slightly thinner wall than other makes such as Hep2O.

Best of luck !

That was the problem - thanks. I have bought a speedfit reducer from 25mm to 15mm, it came with its own insert which was a simple press fit. This rectification took 5 minutes and no sweat. The original insert was too tight a fit. Water board connected up today and 3 cubic metres per hour leak was sorted. Regards.