Can an air admittance valve get stuck?

Author: Mrs. Liliana Daniel  |  Last update: Tuesday, August 19, 2025

Potential issues with air admittance valves All of which are signs that there may be an issue with the air admittance valve. Occasionally the valve may get stuck. In this case, a simple spray of lubricant should help to loosen the valve and ensure it is back in working order.

How do I know if my air admittance valve is bad?

Another way is field testing in a cup of water, Place the air admittance valve (AAV) in a cup as shown below. This creates a positive pressure which seals the membrane and allows the valve to float. If the AAV sinks then most likely the membrane has been compromised which allows air to pass through the AAV and sink.

Why is my air admittance valve not opening?

Another thing you could try is to close off all possible vents , plugs in , overflows bunged up with a cloth and shower trap plugged , then give the WC a long flush . If the AAV is just stuck shut it may be enough to pop it open again .

What is the life expectancy of an air admittance valve?

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.

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.

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

Can an AAV 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.

Why do valves wear out?

Dirty oil causes valve wear, lowering engine compression. Defective valve springs or other parts cause valves to stick open, subjecting them to damage from pistons. Abnormally high operating temperature (for-instance, from over-revving or hard driving) scorches exhaust valves, resulting in heat-stress breakage.

What are the disadvantages of air admittance valves?

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.

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.

Why is studor vent illegal?

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.

Does an air admittance valve let air in or out?

At this stage, air will be required inside the system to stop a negative pressure from forming which would stop the flow of water or drag waste water back up through the traps. This is where the air admittance valve comes in, it is designed to only let air in, and not let any air (or gasses) out.

Why is my AC vent not opening?

If your AC is running and you are not feeling air coming out of your vents, you will first want to check all of your vents to see if you have an issue with just one or with multiple vents. If you notice a lack of airflow in just one area of your home, check to ensure that the registers in this area are completely open.

Do you glue air admittance valve?

Depending on the type of fitting, glue or screw the AAV in place. Look to the manufacturer's directions if you need additional assistance.

Can an air admittance valve get blocked?

Potential issues with air admittance valves

Occasionally the valve may get stuck. In this case, a simple spray of lubricant should help to loosen the valve and ensure it is back in working order. Another reason for these issues is that the waste pipe may be blocked.

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.

What is the difference between an air admittance valve and a cheater vent?

Automatic air vents are spring type devices often referred to as in-line or cheater vents, while air admittance valves have no spring. Air admittance valves are more expensive and are approved in many jurisdictions where in-line and cheater vents are not because of their moving parts (springs).

Can an air admittance valve stop working?

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.

Why is water coming out of air valve?

This is because most air release valves seal around 25 – 30 psi unless a special soft seat is provided. So when the pipeline is filling and pressurizing, your air valve is exhausting both air and water into the exhaust pipe.

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.

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 an air admittance valve be boxed in?

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.

Why are my valves getting stuck?

Stuck valves are usually caused by a build-up of deposits and/orcorrosion on the valve stem. Because the fit of the stem in theguide is so snug, it doesn't take much build-up on the valve stemto interfere with free movement of the valve within the guide.

How do you know if your valves are blocked?

These are the most common symptoms of heart valve disease: Chest pain. Palpitations caused by irregular heartbeats. Fatigue.

What is the most common valve failure?

Any valve in the heart can become diseased, but the aortic valve is most commonly affected. Diseased valves can become prolapsed where they don't completely close; this is called regurgitation. If this happens, blood leaks back into the chamber and not enough blood can be pushed forward through the heart (Figure 2).

Previous article
What do you do if your hot water pipe freezes but not cold?
Next article
Why is my sash window not closing properly?