Washing Machine Piping Puzzle

[Spinny]

@Super_Paulie  Where did you get  this connector ?

 

I have only seen double ones with an air admittance valve to go on the top of a standpipe.

[Super_Paulie]

I think it was this.

[Spinny]

Thanks greatly @Super_Paulie 

So you don't need an air admittance valve when doing that then ?

And I notice you still kept a standpipe like height above the u bend.

[Super_Paulie]

6 minutes ago, Spinny said:

Thanks greatly @Super_Paulie 

So you don't need an air admittance valve when doing that then ?

And I notice you still kept a standpipe like height above the u bend.

 

Each appliance is on its own waste so no AAV. Standpipe just to create the traps.

[Spinny]

So if my toilet basin with it's bottle trap is plumbed to connect into the same 40mm slight horizontal fall waste pipe that my washing machine discharges through do I need to fit an air admittance valve ?

[Super_Paulie]

Id imagine the would make the trap in the basin gurgle as it creates a vacuum when the machine discharges and will pull water from the basin bottle. 

 

Change the bottle for a trap with an AAV built in? Or whack in a 40mm branch with the AAV on one side?