Fit air admittance valve to hard to reach waste pipe

[brig001]

Hi, I have a waste pipe that needs an air admittance valve (when toilet flushes the bath trap empties) and it is barely accessible as everything in the bathroom is boxed in. I could just about fit a self-cuting washing machine waste kit like this https://www.screwfix.com/p/washing-machine-drain-out-kit/75883 but need a straight fitting as I can only get to the top of the pipe. I would then need a way to fit that to an air admittance valve

Any ideas please or is there a better way?

Thanks,
Brian

 

[Hugh Jaleak]

I would investigate first if there not already an AAV on the stack, would be unusual for there not to be. (Could be stuck shut.) Otherwise I'd say your easiest option would be to fit an Anti Vac bath trap. McAlpine 1½" Anti-Siphon Bath P Trap White 40mm | Traps | Screwfix.com

The self cutting waste is no good, you wont be able to connect anything to it other than a hose.

 

[brig001]

Thanks Hugh, I can't get to the stack or the bath trap. There are fitted cupboards from the bath panel side into the corner where the stack would be. The toilet is half-way down the cupboards. Not even sure the stack is there as it is a flat. It all looks really nice until you need to fix anything...

Found this at Toolstation https://www.toolstation.com/mcalpine-clamp1-pipe-clamp/p77260
But would then need to get from 22mm to 40 to fit an air admittance valve. I can do it with 21.5mm waste pipe, but that could be too loose in the compression fitting

Brian

 

[brig001]

Fitted a new anti-syphoning trap to the sink which is 4m away in pipe terms and it seems to be working. I wasn't sure with it being so far away, but so far, so good

Brian