Trapped air in plumbing or heating systems can cause inefficiencies, noisy operations, and even system failure. These issues lead to increased energy costs, discomfort, and costly repairs. The solution? Proper installation of an automatic air vent. This device automatically releases trapped air, ensuring your system runs smoothly. But where should it be installed? Let’s find out.
An automatic air vent should be installed at the highest points of a plumbing or heating system, such as radiators, boilers, or piping loops, where air naturally accumulates. Proper installation ensures optimal performance and prevents air-related issues.
Curious to learn more about automatic air vents and their installation? Keep reading to explore their purpose, functionality, and best practices.

What is an Automatic Air Vent?
An automatic air vent is a small but essential device used in plumbing and heating systems to remove trapped air. Air pockets can disrupt water flow, reduce heating efficiency, and cause noise or damage to the system. The automatic air vent solves these problems by releasing air automatically without manual intervention.
These vents typically feature a float mechanism that opens when air is present and closes when water fills the valve. They are commonly used in hydronic heating systems, radiators, and domestic water systems. Available in various sizes, such as Automatic Air Vent 1/2″, they are designed to suit different applications, from small residential setups to large industrial systems.
Should the Automatic Air Vent Be Open or Closed?
An automatic air vent is designed to operate automatically, so it should neither be manually opened nor closed during normal operation. The valve’s float mechanism ensures it opens to release air and closes to prevent water leakage.
However, during installation or maintenance, you may need to manually open or close the vent to test its functionality or remove debris. Once the system is running, the vent should be left to operate on its own. Interfering with its operation can lead to improper air release or water leakage, compromising system efficiency.
What is AAV in HVAC?
In HVAC systems, AAV stands for Automatic Air Vent. It serves the same purpose as in plumbing systems—removing trapped air to maintain optimal performance. In HVAC applications, AAVs are often used in hydronic heating systems, chillers, and air handlers to prevent airlocks and ensure efficient heat transfer.
AAVs are particularly useful in systems with complex piping networks, where air pockets are more likely to form. By automatically releasing air, they help maintain consistent pressure and temperature, reducing energy consumption and preventing damage to equipment.
How Should an AAV Be Installed?
Proper installation of an Automatic Air Vent (AAV) is crucial for its effectiveness. Here are the key steps:
- Choose the Right Location: Install the AAV at the highest points of the system, such as radiators, boilers, or piping loops, where air naturally accumulates.
- Position Vertically: Ensure the vent is installed vertically to allow the float mechanism to function correctly.
- Ensure Accessibility: Place the vent in an accessible location for easy maintenance and inspection.
- Check Compatibility: Use the appropriate size, such as Automatic Air Vent 1/2″, for your system’s pressure and flow rate.
- Seal Properly: Use thread sealant or Teflon tape to prevent leaks at the connection points.
Following these steps ensures the AAV operates efficiently, preventing air-related issues and extending the system’s lifespan.

What is the Difference Between Auto Vent and AAV?
While the terms auto vent and AAV (Automatic Air Vent) are often used interchangeably, they refer to the same device. Both are designed to automatically release trapped air from plumbing or heating systems. The primary difference lies in the context of their use:
- Auto Vent: A general term used in plumbing and heating systems.
- AAV: A more specific term often used in HVAC systems to describe automatic air vents.
Regardless of the terminology, both devices serve the same purpose—ensuring air-free operation and optimal system performance.
Summary
An automatic air vent is a vital component for maintaining the efficiency of plumbing and heating systems. By installing it at the highest points of the system, you can prevent air-related issues and ensure smooth operation. Whether it’s an Automatic Air Vent for domestic water or an HVAC system, proper installation and maintenance are key.
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