Air admittance valve

[Tomdonny]

Hello, DIY plumber here, I’m after some advice regarding an AAV, my current one goes though the loft and the roof with a vent on, iv seen on some pan connectors have 32mm air admittance valves built on to them. Does this mean I don’t need the 110mm pipe into the loft at all? TIA
Tom

 

[oz-plumber]

AAV's were invented when it was difficult to vent a fixture to atmosphere.
They were intended for single fixtures like basins, troughs and maybe a shower when the distance from the fixture did not fall within the required length of the vented drain.

As for using them to vent a dwellings entire sewer system was not the intended purpose, hence, I have installed probably 1/2 a dozen of them in 25 years - on single fixtures that don't fall within the ventilation requirements.

I wouldn't disconnect your main sewer vent

 

[king of pipes]

Oz is correct you need to vent your drains aav's are not enough especially the smaller size ones they are only a aid to help the flow of waste water from basins , sinks, baths, toilets, ect although tempting to remove pipes and boxings to gain space your asking for trouble theres nothing better than a vent to atmosphere. Kop