Polypipe underfloor heating manifold leaking on the isolation valves when pressurised All aspects of plumbing questions and answers, help, tips and information

[Jaime Hewitt]

Hi lads. I've got a problem with the isolation valves leaking and losing pressure on the underfloor heating that I've put together with the help of my mate who's a plumber. We put it all together, fibre washers in all of them. Left it pressurised over night. I came back the next morning and there was a big puddle under the manifold and all the joints had drips under them. All the joints were as tight as they could be. We've tried doubling up on fibre washers and ptfe! I've changed the iso valves aswell and it's still leaking! I would appreciate massively any advice anyone has. Or if they've faced similar problems with undefloor heating. Its a polypipe push fit system by the way. Cheers.