January 2022

Master-Bilt® Refrigeration News & Product Information


Refrigeration U: What Is A Pressure Relief Port?

Ever try to open the door to your walk in cooler or freezer but it won’t budge? In fact, it feels like it has been welded shut. Don’t worry, your inability to open the door isn’t due to a lack of physical strength. It all has to do with air pressure.

Ideally, the air pressure on the inside and outside of a walk in should be about the same. However, opening a door allows warmer air into the walk in which is quickly cooled once the door shuts. This rapid temperature drop results in a reduction in pressure, making it difficult, if not impossible, to open the door. Differences in temperature and pressure may also be caused by product loading and defrost cycles but the result is the same: a door that is hard to open. Inside and outside air pressure must be equalized before the door can be easily opened.

walk-in pressure relief port

Pressure relief ports allow airflow through the walk in panel which equalizes pressure making easy to open a door.

So what is the solution to the problem? Pressure relief ports, or pressure relief valves, provide the answer. These ports are available in many types and sizes depending on the size of the walk in and the holding temperature. They are usually mounted in the door frame and allow airflow through the walk in panel which equalizes pressure.

In many cases, pressure relief ports are a standard feature, especially on freezer doors. However, if you are considering a cooler or freezer and want to save wear and tear on your muscles, check to be sure that a pressure relief port is included.