22mm Marley PEX pipe split twice in same place

[staddon-smith]

I live in a ground floor flat

The 22mm pipe is connected to a copper pipe with a push fit connector that comes from the Boiler (Potterton) under the concrete floor to the airing cupboard (I think). The first time the pipe split right at the connector about 50mm long split, I cut the PEX pipe back and connected the PEX pipe to a piece of copper pipe with another push- fit connector, and turned the boiler on and about an hour later the outer skin of the PEX pipe has split again.

Do you think this is a faulty pipe for could it be something else.


Thanks