10L Undersink

[emergencyman]

On a 10l undersink water heater is it OK to run the pipe from the PRV into the waste pipe? I have seen hundreds done like this.
Reason I ask is the the instructions suggested way is to run a 22mm copper pipe outside, which is something I want to avoid.
Thanks

 

[BLOD]

Always go with what the manufacturer suggests.
Maybe the mi's say you could fit a vented tap ?

 

[lame plumber]

just follow the instructions as said

 

[emergencyman]

Not instructions, suggestions. That's m point.

Ayhow, fitted it today. Thanks anyhow.