Air Admittance valve in flat

[Hot&Cold]

Air admittance valves for soil/drain have been around for years now.

Aav's on soil terminations and combined on traps work very well but retro fitting an aav to assist in an incorrectly installed waste,soil system is the last resort.Altering the existing drain/waste plumbing should be considered prior to retro fitting an aav.

Question-What did people do before aav's were produced ?

 

[hard-work]

You may find you can't alter a cast-iron soil stack in a block of flats. Many old drain-stacks in old block of flats had a separate air/vent pipe running parallel to the main soil stack. It would be a 1.5 inch lead pipe alongside the 4 inch cast iron soil stack branched into the top of each branch on each floor just behind the WC connection. Many flats now have high flow showers, etc, so amendments must be made like AAV's