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Why Is My Diving Regulator Free Flowing?

Why My Dive Regulator Free Flows

Przemyslaw Tarko |

As a scuba diver, you might have experienced that momentary helplessness when your regulator starts to free flow. While on the surface, this might not be a cause of concern. Still, when it happens underwater, it can lead to life-threatening situations. Free flow on a regulator can stem from several reasons, including design, dirt, freezing, and icing up. Luckily, there are some preventive measures that divers can take to ensure they don't fall into situations like these. Read on to understanding of regulator free flow and tips to prevent it.



Why Is My Diving Regulator Free Flowing?

There are several reasons why regulators can free flow. Firstly, the general build of the regulator means that all manufacturers aim to make work of breathing as smooth as possible. The anatomy of the regulator design, combined with large airflow in a small space, can cause the regulator to free-flow. 

Another reason for a regulator to free flow is because of dirt in the second stage. More often than not, your regulator will start to bubble when the dirt, dust, and sand find their way into the diaphragm. This is a sign that it needs a little bit of TLC. Let's face it. It can be quite a common occurrence in the resort, where divers are not so careful with the rental gear, and we all have seen regulators dipped in the sand rather than the sea.

Free flow due to freezing and icing is yet another reason why you might experience regulator free flow. This is because free-flows due to icing usually start at the first stage, and the high flow of air can then cause the second stage to ice up. While it is highly unlikely in tropical diving, it can definitely happen in temperate and cold waters. If you are diving in cold water, it is crucial to take preventive measures to avoid ice buildup.

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Tips to prevent scuba regulator free-flow:

So, how can you prevent regulator free flow? Firstly, it's crucial to choose a regulator designed for your type of diving - buy the best you can afford. Research the type of regulator you want to buy carefully; some are better suited for cold water diving than others.

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Ensure that the air in your tank is properly dry. If the air in your tank has moisture, it can become a potential cause of freezing. Make sure you fill your tanks from a well-look-after compressor. When you are finally ready for the dive, take your first breaths of air with your regulator submerged rather than on the surface. 

Another critical point is to avoid demanding more air than necessary. This means that you must keep your breathing rate under control while diving. Modern regulators are designed to operate with high gas demand, and some, like the Scubapro MK25 Evo, can get through 9000l per minute. But there are limits, and eventually, every regulator will freeze up in certain cold conditions. Breathe steadily, relaxed and slowly! Additionally, designers often add a venturi plus/minus lever that operates a plate inside your second stage that disrupts the venturi effect making the free flow less likely. When on the surface and getting ready for a dive, keep your regulator positioned mouthpiece down/diaphragm up when your regulator is out of your mouth. 

Lastly, practice breathing from a free-flowing regulator by purposefully pressing the regulator's purge button. This will keep you informed and refreshed about how to handle such situations in the unlikely event they happen underwater. Practice out-of-air drills with your buddies.


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Regulator free flow is a frustrating problem that almost every diver faces eventually. Understanding the catalysts of this problem and how to prevent it can help ensure that you have a safe and pleasurable diving experience. By following these tips, you can make sure that your regulator is free-flowing less often. Remember to invest in a good regulator and maintain it regularly, as well as thoroughly inspect the tank in required testing intervals. Happy and safe diving!