Waste pipe for pressure relief under sink heater

[Fallout]

I no there are strick regs on the material on the waste pipe for a pressure and temperature relief on a large over 15litre unvented cylinder. But the small under sink ones there is not as they just have a pressure relief. Is that right? So it can just go in to pushfit waste via a hepvo trap.

 

[Madrab]

Do as the MI states, can't go wrong

 

[Newboy]

Quote from the Wavin website

"Exclusions: The HepVO® should not be used for uncontrolled high temperature discharges such as from pressure-only relief valves (i.e. not incorporating a temperature relief valve)."

I'd say that's a no!

I wouldn't consider using any form of pushfit waste pipework on an unvented of any size

 

[OwainDIYer]

AIUI the installation regulations are the same, it's just that under 15 litres the installation is not notifiable to Building Control and does not need an annual inspection.

 

[Fallout]

So should be solvent weld if using plastic. And with its own connection to the main drain.ie not tee d in to any other wastes?

 

[OwainDIYer]

So should be solvent weld if using plastic. And with its own connection to the main drain.ie not tee d in to any other wastes?

Sounds good.

You don't want to be sitting on the bidet when the pressure relief backfeeds up a shared tee.