Air admittance valve‎

[sasik]

I would like to know if there is any circumstances when you should not use Air admittance valve‎? I have just finished to renovate a bathroom in an old house. I fitted a new bathroom, we didn't alter the waste pipes or soil pipes which are all running under the floor. The only change I made was, removing the vent pipe (part of the soil stack) from outside the property and fitting new Air admittance valve inside the property (boxed in).
The customer complaining about bad smells in the new bathroom. I know that the pipe work is water tight (because i have tested it). But it is seems to me that it might not be air tight! This take me back to my original question, should I or shouldn't I used the Air admittance valve‎?

Thanks

 

[warrington]

Air admittance valves should,t be used on discharge stacks connecting to a drain which has an Intercepting Trap or to drains whisch are subject to Surcharging as it could result in trap seal loss of appliances.

 

[warrington]

'should,t' meant 'should not'

 

[mikegas]

the aav shouldn't be boxed in

 

[nysk2008]

Couple of things are AAV has to fitted on the vertical, if the valve is fitted inside a duct, the duct will require ventilation,

Air admittance valves should not be used when the discharge stack provides the only ventilation to septic tanks or cesspools. Have you fitted it above flood line? Try taking the valve off and check all traps. Im pretty sure it is approved document H that you wanna have a look at to get all the do's and dont's​

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[Deleted member 25704]

Sanitary is derived from the Latin sanitus, which means health. Sanitary installations rely on traps seals to prevent toxic and dangerous gases entering the building - we kind of take this for granted, but if we considered what happenned in Hong Kong and SARS break-out, we would think again.

Bottom line - open ventilation of a sanitary system is proven, safe and dependable.

Fitting a mechanical device to do the same is a poor decision, in terms of protecting the customer's health.

Solution, get rid of AAV and install open vent again.

 

[Guest123]

The new generation of AAV's do not require you install them above the flood line of the highest appliance. There are now external ones too that are gauranteed to be protected from insects, vermin, frosts and extremes in temperature. It's preferable to drill a hole through your external wall and fit one outside than fit one in a boxed in pipe chase.

They have been incorrectly fitted in many of the public buildings I work in, putting full blocks of toilets out of action causing mayhem to office staff and school kids.

 

[sasik]

Thank you all for your comments. There no lost of seal in any of the anti vac traps I have fitted on site. The property is located on the top of a hill, so flood line is not an issue. The box witch the AAV positioned in is ventilated and the system is working perfectly (well almost). My theory is that, the system (for some reason) is not air tight. Before the new AAV was fitted the bad smells were venting out of the system regularly. But now the new AAV keep all the bad smells in the pipe work eventually the smell find it way out.

Your thought please!

 

[WHPES]

Have you pressure tested the system for leaks?

 

[AWheating]

might be an upward facing socket on the soil which holds water but allows air to escape. bung and air test system to try and find the leak or reseal around every seal. or it could be a faulty aav?

 

[fuzzy]

not the only ventilation on a stack system. its ok if end house have full ventilated stack

 

[sasik]

I think you are right AW! unfortunately the whole bathroom is tiled over!!! So, the AAV have to go and an open vent will be fitted back on!

 

[Stephen Hale]

Anyone - I have a similar problem with an internal toilet off a bedroom which is at the head of the run. A hand basin AAV has been fitted above the sink overflow level but there are still bad odours coming from the system. I can't fathom where these are coming from as all traps seem to be full and there are no leaks on the pipework. Are the 40mm AAVs as successful as a full 110mm one? Any thoughts on further actions here?

 

[Derek Hardman]

Flush the loo and see if the water in any of the traps is pushed back up (it doesnt need to push the water all the way to the top of the waste, just lifting it proves insufficient vent), have seen this before and took a while to find the problem.

 

[Mike Jackson]

Have a sniff of the overflow on the basin. If the waste has been incorrectly fitted, or the wrong waste fitted you can get water stagnating in the overflow.

 

[SafeGasInstall]

I think your aav is faulty ! they should only open when water is flushed and negative pressure is created in the soil pipe !