How to Do Negative Pressure Tests on SCUBA Regulators

Checking out your regulator prior to diving just makes good sense. In a very literal sense, your regulator is your life line. It is your source for air underwater. A malfunction can result in several nervous minutes and a shortened dive at best or serious injury or death at worst. Negative pressure checks are something most SCUBA divers have done and just have not been familiar with the term.

Instructions

Difficulty: Easy

Things You’ll Need:

Buoyancy compensation device Submersible pressure gauge Alternate air source (Octo) First stage regulator Second stage regulator
Buoyancy compensation device
Submersible pressure gauge
Alternate air source (Octo)
First stage regulator
Second stage regulator

Step 1

Connect your regulator rig to the scuba tank as you were taught in your certification class. Connect your buoyancy compensation device to the regulator rig. Your second stage, alternate air source and submersible pressure gauge should already be connected to the first stage. If they are not or if you have questions on how to assemble your gear, consult your dive master for proper assembly.

Step 2

Open the valve on your SCUBA tank. Check your pressure gauge to ensure the tank is full. Listen for sounds of hissing air that might indicate a leak.

Step 3

Insert your regulator into your mouth as you would while diving. Apply negative pressure to the regulator by inhaling through your mouth. This should cause the regulator to activate and let you easily inhale low pressure air from your tank. If the regulator is functioning properly, it should stop supplying air when you stop inhaling. If air continues to flow after you stop inhaling, your regulator is not functioning properly and must be serviced and inspected by a professional before use.

Step 4

With the regulator still in your mouth, slowly exhale through your mouth. It should allow you to exhale without releasing air.

Step 5

Repeat steps 3 and 4 with your alternate air source regulator.

Tips & Warnings

When you inhale during your negative pressure check, taste the air as well to ensure it is suitable for diving. Bad or odd-tasting air may be a sign of a contaminated air supply and you should not dive with this tank.

Even with well-maintained gear and quality training, diving can be dangerous. Only dive using equipment that has been inspected and serviced in accordance with the manufacturer's service interval recommendations. Failure to do so can result in equipment failure, which can lead to serious injury or death.

Resources

Article Written By Diane Hansen

Diane Hansen has a thirst for adventure and loves to share the world through the written word. Currently, she is the feature editor for "TRAVELHOST" magazine and is working on her first novel. She graduated from Cal State San Bernardino in 2002 with a B.A. in business administration with a concentration in marketing. She has been writing freelance since 1996.

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