unvented cylinder discharge pipework

[sparky]

Hello everyone,

Gone through unvented book bpec to find answers to "can i use solvent weld pipe when terminating into a soil stack" Anyone have an answer?

 

[Ockyvines]

You cannot use solvent weld pipe on unvented discharge, it has to be high temp pipe (which nobody seems to stock)
Nothing else can tee into the pipe either, baths, basins etc. and you need to use a Hep v trap vertically as it exits the cylinder

 

[sparky]

Been told push fit fittings are ok. The main run of pipework is in 28mm copper about 9 metres then into a hepvo valve and 1 solvent elbow into solvent adapter to soil ground floor.

 

[Ockyvines]

I'm not sure that all push fit is high temp. Abs solvent weld definitely isn't.
9 m of 28mm copper is fine.the Hep valve must be vertical.

 

[sparky]

Hepvo valve literature says can be fitted horizontal ribs on bottom? know any different?

 

[Ockyvines]

They can only be fitted vertically if being used on unvented discharge pipe.
Horizontal is ok for standard waste pipes

 

[sparky]

That i didnt know! Any reason for this do you know?

 

[Ockyvines]

I'm not sure, It's prob because of the possibility of extremely hot water discharge which could melt it.