Air admittance valve

[m4ckg]

What is the lowest the valve can go? If I can't get it low enough I'll have to go out through the wall and return it vertically. Am I right in saying it will have to go 600mm above the soffit or is there anything new on the market which could go lower ?

[Ferg]

Above the level of the basin spillover is what most Building Inspectors want.

[mk1fan]

If you're venting externally you need to be above any opening, if there's Veluxs in the roof then you may need to go over them.

If you can get the aav high enough then you'l also need an access panel to it.

Edited by mk1fan on Friday 11th February 10:49

[m4ckg]

the only thing that has thrown me is a neighbour of mine has a bungalow and her AAV finishes just below her bathroom window! that can't be right can it or has she got a new product to overcome the problem ?

[Ferg]

Is it outside?? That's never a good idea.

Essentially the rules are that a SVP must be of a size to replace the air drawn in by the syphon action of the drain. The vent must terminate 900mm above any opening window within 3 metres.

HOWEVER....
The BBA do allow the use of Air Admittance Valves on a SVP PROVIDED it isn't the head of the drain run, it's above spillover level and it is accessible for servicing.

[BRGV8S]

AAV not acceptable for external fitting, they freeze up. As above S&VP 600 above any opening and at the head of drain run. AAV internally and terninate above the the outlet of the highest appliance

[Simpo Two]

Mine's under the bath, well, next to it

But it works just fine.

[andy43]

If it sticks open due to, err, sticky things causing a blockage, it's poo too low.