Air Admittance Valves – How Safe are They?
(Air Admittance Valve = A.A.V)
There is debate on whether or not air admittance valves should be used in plumbing systems. Most codes will allow the use of an air admittance valve as long as the AAV is certified by a safety comity such as the C.S.A. They do sell non approved air admittance valves in hardware stores. The difference in cost is typically a lot. For example a CSA approved AAV could cost anywhere from $30-$50 whereas a non approved AAV sells for around $5-$10. Many people cheap out on the AAV and this is not where you should try to save money. There are some problems that can occur with a cheap AAV that could harm your health.
What Problems Can an Air Admittance Valve Cause?
The most common problem that occurs with an AAV is that the check valve inside the device can get caught open. When the check valve in the air admittance valve is stuck open, There is nothing holding back sewer gases from entering your home. This is a pretty obvious health issue in your home. There are noxious and dangerous gases in the sewer pipes that can potentially be harmful. This is why you want to spend the little extra and purchase an AAV that is CSA approved. the check valves in a CSA approved air admittance valve function better , they are tested, and less likely to get stuck open.
Another air admittance valve problem is they often times covered up behind drywall or hidden. An AAV should always be accessible. The vent should be maintained regularly to prevent failure of the device. a homeowner should check the device monthly to ensure it is working properly.
How to Test an Air Admittance Valve
To test an air admittance valve make sure that the AAV is accessible. Fill a sink that the valve is venting to the top. Let the sink drain and listen to the valve as the sink drains. You should be able to hear the AAV pulling in air from the room. You can even put your hand over the valve to make sure. Once the sink has finished draining the check valve in the AAV will close. If the check valve closes than the air admittance valve is working properly.
If you are still not sure if the AAV is working or not you can remove it from the pipe. Once removed hold the valve straight up and blow into it with your mouth completely sealing the bottom. If you can blow air out of the air admittance valve than the check valve is not working and you should replace it. (clean the air admittance valve before putting your mouth on it).