I've recently moved into a flat which has the following under the sink - can anyone tell me what it is? :
There is an earthy/stale/cabbage smell coming from it. Have tried bleaching it but the smell comes back.
Any advice appreciated.
cheers, Trenton
Yes, it's an air admitance valve (AAV). It allows back pressure in the soil pipe to be released, and is an alternative to a vent to the outside in some situations.
It's probably blocked. You can get a new one from any plumbers merchants. About GBP15.
Jon.
It looks like a vent for the soil stack to me... Even if it is allowed, I wouldnt fancy one under my kitchen sink!
Why? They are absolutely fine if working properly. This one clearly doesn't (it should not allow smell to come out) - it has a one-way membrane in it which that only allow air in one direction (into the soli pipe, and not out).
ITYM it relieves any partial vacuum in the soil pipe by admitting air. It shouldn't release pressure in the soil pipe! CUrrently it probably is though :o(
Remember that it's supposed to be fitted above the flood level of the appliances feeding it, for example above the overflow level of a sink.
Why? The words 'if' and 'should' when it comes to whether I am going to smell poo in my kitchen or not are my main reasons. I do appreciate that there may be situations where this arrangement is the only choice but if it was my install I would only have it as a last resort.
Fair enough - I agree. I have done up several flats with internal kitchens over the last couple years where this was the only solution available whic is why I am probably pretty used to the idea.
Couldn't agree more,the thought or arrangment of having a shit pipe in the kitchen is not on. On saying that I've just had one removed out of my kitchen even though it was boxed in,if there is no other option which I find is hard to believe then fine but if it can go outside then thats the place and only place it should be.
As others have said this is an air admittance valve. Very likely it's failed and is letting out air and smells.
AAVs are not allowed on the most upstream soil stack.
I don't follow. Why not on the most upstream?
Yes indeedy, I've got one on my one and only soil stack that was originally boxed in in the bathatorium. Is this OK ?
It got truncated when the bathatorium was re-worked into a showeratorium and is now terminated with a durgo valve under the worktop next to the wash basin.
Occasional damp / foul smells permeate the showeratorium. Seemingly if the door has been closed for a few hours. However I can not eliminate the possibility that leaks from ultra crappy quailty chinese basin waste remote controlled plug mechanism are not encouraging the crappy quality cabinets (Apparently made of veneered weetabix) to rot away.
It's 38 years since the Niel Armstrong got out of his spaceship on the moon, and we are living like this.
DG
Maybe if you'd spent as much on the showeratorium as NASA spent on Neil's spaceship, you'd have got something better than veneered weetabix.
Or maybe it just wouldn't have fitted because they'd confused inches and cms.
Owain
I spent more than enough, the contractor didn't ask for more. Now I simply want it to work. It looks like it's myself that will have to make it work which is what makes it a uk.d-i-y issue.
Yebbut that would have been their problem.
As it stands (or falls !) I'm stuck with it :-((
And it is built of very ordinary components/materials. Which makes me wonder do these valves fail a lot in such a condition that they admit smells into the room ?
DG ( gOwain away if the smell doesn't)
Thanks to all for your help. Sounds like I should get on to the letting agent for a plumber, rather than fiddle about with it myself.
cheers.
If it's a rented place why would you touch it anyway?
This was the rules as given to me by a BCO. He seemed a reasonable chap and not one to gold plate the regs. Apparently the most upstream inspection chamber must be open vented via at least one soil stack . There is no reason not to use AAVs on other soil stacks even ones that go to to the same chamber.
He also said that the common practice of dropping grey water into a hopper and then into a downpipe was also wrong. I pointed out that there must be
5 million houses in the UK that do that and asked when did this rule come in. He said it was it was lack of enforcement at the time the rule was there in the 1930s.
Ah, yes, now I think about it, one would want something to vent lighter than air potentially explosive gases
Meaning soil stack or rainwater downpipe?
Both, but the level of compliance on the latter is very poor.
He also mentioned that the grey water wastes that discharge into a gulley must go down through a gulley grid, and exit above the water level in the gulley trap. There must be 10 million homes which breach that one! Another BCO but who I think gold plates the rules said the shower waste had to go direct to the soil stack - that's got to be over the top.
I was under the impression that before a certain date, it was common practice to combine surface and foul drains or was the point that they should be separate above ground regardless of what happens below?
Several houses that I've lived in in the past had the exterior hopper and downpipe arrangement but it always fed into a gulley.
I don't see the logic of that one. Pehaps that he thinks that people piss in the shower but not in the bath.
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