Difficuty fitting an Air Admittance valve - AAV Drainage and wastage systems and plumbing help, advice and answers

[spooky]

The plumber omitted to fit an AAV when installing our ensuite - probably because of difficulty of access.. I dont think its possible to fit a 110mm AAV because of lack of space but there is room to get some 32mm pipe connected. The question is will a 32mm AAV work satifactorily if it is connected to a 110mm waste system?

[peter the plumber]

Is your soil pipe below a window or is it 3 meters above the top of the window?

If your soil pipe is below a window you need an AAV, but if it’s above it you don’t.

I would get your plumber back if it’s below the window level and let him sort it out.

A 32 mm AAV would work but you may have a problem with your household drainage, (slow flowing) and don’t let your local council building inspector see it

[gerald_s_wright]

providing you have 2 independant connections to the soil stack it is possible to use HepVo traps in place of conventional traps with no requirement for an air admittance valve provided other properties in the area (1in 10) has conventional vent stack and your property is not on a septic tank. This method comforms with building regulations.