An Air Admittance Valve (AAV), also known as a Studor Vent or Sure Vent, is a mechanical device used in plumbing systems to allow air to enter the drainage system and prevent negative pressure that could otherwise impede water flow. AAVs serve as an alternative to traditional venting systems by eliminating the need for roof penetrations and offering a cost-effective and time-saving solution for venting plumbing fixtures. This article provides a detailed, step-by-step guide for the proper installation of an AAV, based on the instructions and specifications found in the source materials.
The installation of an AAV is subject to local plumbing codes, manufacturer specifications, and the type of pipe being used in the system. AAVs are typically installed vertically and must be positioned correctly to ensure proper function and accessibility for future maintenance or replacement. The sources reviewed emphasize the importance of verifying local code requirements before proceeding with the installation. Additionally, the materials and tools needed for installation are outlined in the source materials, including PVC primer, cement, thread sealant, and a deburring tool.
The following sections will cover the key considerations for selecting and installing an AAV, the required tools and materials, the step-by-step installation process, and tips for verifying that the AAV is functioning correctly.
Understanding Air Admittance Valves
An AAV is a one-way mechanical valve that is installed at the site of a plumbing fixture to allow air to enter the drainage system. It operates by opening to admit air when negative pressure is created within the system—such as when water is draining from a sink or toilet—and closing when the pressure is balanced. This function prevents sewer gases from entering the home and maintains the proper flow of water through the system.
According to the source materials, AAVs are particularly beneficial when connecting to an existing venting system is not feasible or when minimizing roof penetrations is a priority. They are commonly used in under-sink fixtures, vanity units, and other locations where traditional venting might be difficult or impractical.
AAVs are available in various designs, but all perform the same essential function. It is important to note that while AAVs are widely used, their installation is not always permitted in all jurisdictions. Therefore, it is crucial to consult local codes and manufacturer guidelines before proceeding with installation.
Key Considerations for AAV Installation
Before beginning the installation of an AAV, several key factors must be taken into account to ensure that the valve functions properly and complies with local regulations.
1. Local Code Compliance
The use of AAVs is not universally permitted in all areas. Some municipalities have specific restrictions or requirements for their installation. It is important to verify that AAVs are allowed in the intended application by consulting local building codes or a licensed plumber. If AAVs are not permitted, the fixture must be vented through the existing venting system.
2. Manufacturer Specifications
Each AAV manufacturer may have specific installation instructions that must be followed. These guidelines are typically included in the product documentation and should be reviewed before installation. The source materials mention that AAVs must be installed vertically and must be accessible for inspection and potential replacement.
3. Pipe Material Compatibility
AAVs are typically supplied with adapters made of either PVC or ABS. It is essential to ensure that the adapter is compatible with the pipe material being used in the system. For example, AAVs with PVC adapters should only be used with PVC pipes, while those with ABS adapters should be paired with ABS pipes. Using incompatible materials can compromise the integrity of the connection and lead to leaks or improper function.
4. AAV Placement
The placement of the AAV is critical to its performance. According to the sources, the AAV must be located within the maximum developed length permitted for the vent and installed at a minimum of 4 inches above the horizontal branch drain. Additionally, it should be installed at least 6 inches above any insulation material and within 15 degrees of vertical. AAVs must not be permanently covered and should be installed in a location that allows air to enter the valve.
Tools and Materials Required for AAV Installation
The following tools and materials are typically required for the installation of an AAV:
- Safety gloves: To protect hands during installation.
- Tape measure: For accurate measurements of pipe lengths.
- Pipe cutter or hand saw: For cutting the pipe to the correct size.
- Deburring tool: To remove any rough edges from the cut pipe.
- PVC primer and cement (for PVC pipes): To create a strong bond between the pipe and adapter.
- ABS cement and cleaner (for ABS pipes): For use with ABS pipes and fittings.
- Thread sealant tape: To ensure a tight seal between the AAV and the adapter.
The source materials emphasize the importance of using the correct type of cement and primer for the specific type of pipe being used. For example, if working with PVC, Oatey® Regular Clear PVC Cement and Oatey® Purple Primer should be used. For ABS, Oatey® ABS Medium-Bodied Black Cement and Oatey® Clear Cleaner are recommended.
Step-by-Step AAV Installation Process
The installation of an AAV involves several precise steps to ensure that the valve is properly connected and functions as intended. The following procedure is based on the instructions provided in the source materials.
1. Prepare the AAV
Before installation, the protective plastic film or packaging from the AAV must be removed. This step is important to ensure that the valve is ready for installation and can function properly. Directional fittings should be used when installing the drains and AAV extension to maintain the correct flow of water and air.
2. Locate the Installation Spot
The AAV must be installed at a minimum of 4 inches above the horizontal branch drain and within the maximum developed length permitted for the vent. It should also be installed at least 6 inches above any insulation material and within 15 degrees of vertical. The AAV must be installed vertically and must be accessible for inspection and potential replacement.
3. Measure and Cut the Pipe
Using a tape measure, determine the length of pipe needed to connect the AAV to the drain system. Once the measurement is confirmed, the pipe should be cut using a plastic pipe cutter or hand saw. After cutting, the pipe should be chamfered and deburred to ensure a smooth surface for bonding.
4. Attach the Pipe to the Adapter
The cut pipe should be solvent welded to the provided adapter using the appropriate cement and primer for the type of pipe being used. For PVC pipes, Oatey® Regular Clear PVC Cement and Oatey® Purple Primer should be applied. For ABS pipes, Oatey® ABS Medium-Bodied Black Cement and Oatey® Clear Cleaner are recommended. The adapter should be securely attached to the pipe to prevent leaks and ensure a strong connection.
5. Install the AAV
Once the pipe is attached to the adapter, thread sealant tape should be wrapped around the male threads of the AAV. The AAV should then be inserted into the adapter and rotated clockwise until it is tightened securely. This step ensures a tight and secure connection between the AAV and the adapter.
6. Check for Leaks
After installation, it is important to check for leaks. If the AAV is installed under a sink, the sink can be filled with water to check for any signs of leakage. If no leaks are present, the AAV is likely functioning correctly.
Verifying AAV Functionality
Once the AAV is installed, it is important to verify that it is functioning correctly. AAVs typically last between 20 and 30 years, but their performance can be affected by environmental factors such as dust or debris.
One method to check if the AAV is working properly is to remove the valve and shake it. If the valve is functioning correctly, the diaphragm inside should rattle when shaken. If no noise is heard, it may indicate that the AAV has failed. Another sign of failure is the presence of sewer gas in the home, which suggests that the AAV is no longer closing properly.
If an AAV is suspected to be faulty, it should be replaced immediately to prevent potential issues with the drainage system. AAVs should be installed in a location that allows for easy access to facilitate future replacements or inspections.
Additional Installation Tips
The following tips can help ensure a successful AAV installation:
- Follow Manufacturer Guidelines: Always consult the manufacturer’s instructions for specific installation requirements and recommendations.
- Ensure Vertical Installation: AAVs must be installed in a vertical position with a maximum deviation of 15 degrees from plumb.
- Allow for Airflow: The AAV must be installed in a location that allows for adequate airflow to ensure proper function.
- Avoid Permanent Covering: AAVs should not be permanently covered or obstructed, as this can prevent air from entering the valve.
- Use the Correct Tools and Materials: Using the correct tools and materials for the installation ensures a secure and leak-free connection.
Conclusion
The installation of an AAV is a critical step in ensuring the proper function of a plumbing system. When installed correctly, AAVs provide an effective and cost-efficient solution for venting plumbing fixtures without the need for traditional venting systems. The key to a successful installation is following local code requirements, using the correct tools and materials, and ensuring that the AAV is placed in the correct location.
By adhering to the manufacturer’s guidelines and following the step-by-step installation process, homeowners and DIY enthusiasts can install an AAV with confidence. Regular inspection and maintenance can help ensure that the AAV continues to function properly over time.
For those planning to install an AAV, it is important to remember that the valve must be installed vertically, be accessible for inspection, and be placed within the maximum developed length permitted for the vent. These steps will help ensure that the AAV operates as intended and provides reliable performance for years to come.