How to tell if AAV is failing?

Author: Dr. Granville Runte V  |  Last update: Monday, May 5, 2025

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.

How to tell if AAV has failed?

Probably the most common sign of AAV failure that I see is a faint septic odor, usually due to the flapper valve losing it's flexibility and not sealing/seating properly. If the valve sticks in the sealed position and stops admitting air, then you can get different ``non-venting'' indications.

Can an air admittance valve fail?

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.

Do air admittance valves wear out?

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.

What is the life expectancy of an air admittance valve?

Their lifespan can range from 10 years to 20 years and if they are starting to fail it may be time to replace them. Remember Air Admittance Valves are mechanical and do need to be replaced over time as routine maintenance.

Air admittance valves for plumbing venting explained, [just over 4 minutes]

Can water come out of an air admittance valve?

In order for a liquid to come out, air must come in. All DWV plumbing systems require at least one vent penetration through the roof line, which allows air to enter the system, while also permitting sewer gas to escape.

What are the symptoms of the air admittance valve?

Potential issues with air admittance valves

Sometimes unwanted smells may be emitted, gargling sounds may occur or wastewater comes up from the soil pipes into the sink. All of which are signs that there may be an issue with the air admittance valve. Occasionally the valve may get stuck.

Why does my air admittance valve smell?

If there is an issue with pressure in the pipework system and not enough air is able to be drawn in, it can cause problems such as waste water coming back up from the traps. If you've ever smelt that “drain smell” coming from a plughole then this is likely what is happening as it stops the traps from working correctly.

How long will a studor vent last?

check with the local AHJ (Authority Having Jurisdiction) for more information. Studer vents are certified to reliably. However, anything mechanical can and will fail. Few manufacturers claim they are better for 500,000 uses (about 30 years of use).

What is the downside of the air admittance valve?

The other potential problem with using an AAV instead of a vent pipe is that if you ever get a blockage in the system that prevents the gasses from being pushed down into the sewer, those gases will have nowhere else to go.

Are cheater vents legal?

Sometimes called "cheaters," these tubular, spring-loaded $5 vents are rated for only 1/2 DFU (drainage fixture unit), and are not allowed under most building codes.

Where are air admittance valves not allowed?

Air admittance valves are not permitted in spaces where pressure conditions adversely affect the valve's operation. They are also not allowed in concealed wall and ceiling spaces used as plenums as part of an air distribution system that is under negative or positive pressure.

How long does an AAV last?

How long does an AAV last? Adeno-associated viruses (AAVs) are stable for several months to years when stored properly at -80°C.

Can you test a studor vent?

How do I know if the AAV is working? The most accurate way to test an AAV is by using a manometer. However this may not be readily available. Another way is performing a field test in a cup of water, Place the air admittance valve (AAV) in a cup as shown here, on page 4.

Where should AAV vents be placed?

It must be located a minimum of 4” above the horizontal branch drain, 6” above any insulation material and within 15 degrees of vertical.

Why is there a weird smell coming from my floor vent?

Mold and Mildew

If the smell is musty or similar to that of dirty socks, mold may be growing in a nearby air duct or on the vent itself. A local water leak can cause mold/mildew to grow near the vent. Another possibility is a small roof leak.

What is the minimum height for AAV?

The stack-type AAV shall be located not less than 6 inches (152 mm) above the flood level rim of the highest fixture being vented. The AAV shall be located within the maximum developed length permitted for the vent.

Is my air admittance valve working?

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.

Does an air admittance valve stop smelling?

Now, the AAV stops any smells coming into the loft, but still allows the negative pressure to be filled via an easier method than via the sink, shower, basin traps.

What are the rules for air admittance valves?

An AAV requires a free movement of air around the valve to ensure correct and effective operation. If an AAV is installed within a duct or riser it is important that this area is vented. Ventilated grilles or discreet gaps around the boxing may be an option. For further information see NHBC Technical Guidance 8.1/16.

Will an air admittance valve help a slow drain?

These valves not only save space but also help keep sewer gas out of your home, promoting cleaner air. If you notice slow drains or gurgling sounds from sinks, it might mean there's negative air pressure in your drainage system, and that's the ideal time for these valves to be beneficial.

Can you use an AAV to vent a toilet?

Air admittance valves are a practical option for venting toilets, but it's crucial to follow local rules.

What happens if water gets into vent?

Water buildup in your air ducts is never a good thing. It can promote mold, bacteria and fungi growth which may cause health problems. water in air ducts, believe it or not, is not quite uncommon and can be caused by HVAC system or by other elements such as leaky pipes or leaks in your roof.

How do I know if I need an air admittance valve?

AAVs are ideal for applications such as kitchen-island sinks, remote bathrooms, and remodeling jobs. They offer cost and time savings to the homeowner and labor and material savings to the installing contractor.

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