It is acceptable to oversize a Sure-Vent®; however, an undersized Sure-Vent® will not allow the plumbing system to breathe properly. At zero pressure the Sure-Vent® AAV is sealed, ready to react to pressure changes. The Sure-Vent® AAV will not allow sewer gas to enter the structure.
Individual and branch air admittance valves shall be located not less than 4 inches (102 mm) above the horizontal branch drain or fixture drain being vented. Stack-type air admittance valves shall be located not less than 6 inches (152 mm) above the flood level rim of the highest fixture being vented.
The main problem with using an Air Admittance Valve instead of a Soil Vent Pipe, as discussed earlier, is that by preventing the gases from escaping through the top of the soil stack you are causing them to be forced down into the main drains and sewer system instead.
Air admittance valves have a typical life expectancy of 20-30 years, so if you start to have issues with sewer gases or smells being released around your sink or in the attic-wherever installed- the air admittance valve could be faulty or failed and should be replaced as soon as possible.
Air admittance valves can be installed externally, but this is not very common and is usually only done if the soil pipe is too close to an opening window. Open pipe outlets must be installed more than 3 metres away from a window that opens, but air admittance valves can be closer than this.
AAVs are typically available with 1 ½”, 2”, 3” and 4” adapter connections. The adapter size is based on the diameter of the vent pipe it is being installed on. Generally, a vent should be sized to be half the pipe diameter of the drain it is serving (refer to local codes for specific vent size recommendations).
Foul Odours and Health Concerns
If a soil vent pipe becomes blocked or damaged, foul odours from trapped gases can infiltrate living spaces.
The Studor vent lets that air to be sucked in the pipe during water flow but doesn't let sewer gas escape out. Code is the thing that determines pipe size and also water flow. Hence no studor vents are permitted to toilets because more air is required to keep water flow going with more waste added to the toilet.
To see if the AAV is working properly, take the valve off and shake - if you shake hard enough you should hear the diaphragm rattling. If you hear no noise the AAV may have failed. Additionally, smelling sewer gas is another sign that the AAV has failed in the open position.
Individual and branch air admittance valves shall be located not less than 4 inches (102 mm) above the horizontal branch drain or fixture drain being vented. Stack-type air admittance valves shall be located not less than 6 inches (152 mm) above the flood level rim of the highest fixture being vented.
They are not illegal in California as a state because California Plumbing Code allows "Engineered Vent Systems" see Section 911.0.
Providing it is fitted correctly, there is little that can go wrong with an air admittance valve and this will be largely due to the valve malfunctioning or failing over time.
While this is rare, it is possible. Remember that these valves should last anywhere from 20 to 30 years, so if they are only lasting for a couple of years, there may be some problems that need addressing.
AAVs can vent more than one fixture, but their capacity must be matched to the total DFUs on the branch line they vent. AAVs range in capacity from 6 to 500 DFUs. To vent a clothes washer with an AAV, I run a 1 1/2-inch pipe up from a tee located about 4 inches behind the 2-inch trap, terminating it in the washer box.
How high should you install the air admittance valve? The short answer is a minimum of 200mm above any water entry point. So if you imagine your soil pipe run, then durgo valve / AAV must be fitted above the highest connection to the soil pipe from any sink, bath or toilet that is connected to it.
Yes. Any AAV can malfunction or not operate properly because it is a mechanical device. Signs of that the Sure-Vent is not operating as intended, are foul odors.
How long does an AAV last? Adeno-associated viruses (AAVs) are stable for several months to years when stored properly at -80°C.
The AAV's vent-tee connection needs to be above the trap weir (high-water level) in order to work correctly. Usually, within 5 feet of the trap. The AAV itself should be 4" above that -- it's why the Magic Vent kit has a small riser for the AAV.
An Air Admittance Valve (AAV), which you may also hear referred to as a Studor Vent, Studor AAV or Mini Vent, is a one-way mechanical valve that is installed locally at the site of a plumbing fixture, allowing proper venting to occur without a connection to a larger venting system and stack vent.
Where an AAV is enclosed in a boxing the boxing should be ventilated. The use of ventilation grilles, discreet gaps around the boxing or ventilation of the boxing into a ventilated roof void are some acceptable methods of providing ventilation.
The Studor valve must be installed a minimum of 4" above the horizontal branch the horizontal branch drain or fixture drain being vented. Studor AAVs must be installed within 15 degrees of the vertical position. Studor valves can be installed below the flood rim level of the fixture.
If they run directly to the outside of a building, they should terminate at least 900mm above any opening to the building (e.g. window or door) that is 3 meters or less horizontally from the vent pipe.
Technically, a soil pipe (i.e. a black, white, or grey 110mm pipe) should only be installed above ground. Once the soil pipework goes below ground, it should be connected to a terracotta foul water drainage pipe.
If you have downward-sloped pipes, your toilet will most likely work without a vent. Gravity does a lot of the heavy lifting anyway. However, using the toilet without a vent means you don't have any protection against gases traveling up your drain pipes and into your home.