Although modern regulators are painstakingly designed to offer great reliability, sometimes things go wrong. What should you do if your regulator free-flows at depth?

Balanced, environmentally sealed, cold-water rated — modern regulators are carefully designed, manufactured and tested to provide excellent performance. Decades of product evolution means that today’s regulators offer easy breathing and reliability that dive pioneers could only dream of. Nevertheless, for various reasons, they may fail and free-flow at depth. In this situation, the downstream valve in the second stage of the regulator sticks wide open. It continuously delivers gas, rapidly draining your tank and leaving you in your own personal Jacuzzi. So what should you do if your regulator free flows at depth?

You may have seen new divers inadvertently dropping their regulator face-up in the water at the surface during training dives. Their regulator hisses and spits like an angry snake. Someone may confidently stride or roll into the water from a dive boat with their octopus clipped in incorrectly, then float back to the surface surrounded by bubbles. At the surface, a free-flowing regulator is an annoyance. But a regulator locked in free-flow at depth is potentially dangerous. So, how do you avoid the situation? And what do you do if it happens?

Prevention is better than cure

Much like any piece of equipment, scuba regulators function better when serviced regularly. Manufacturers spend enormous amounts of money on regulator research and development, and set service recommendations for inspection, testing, lubrication and part replacement. Not servicing your regulators means they’re much more likely to breathe inefficiently at best and malfunction at worst. Don’t skimp on servicing.

Check the manufacturer instructions for your regulator. If you can’t remember whether you’ve had it serviced within the recommended guidelines, take it to your local dive shop. Once it’s been serviced, take it on a gentle test dive before moving on to the big stuff. Sometimes, despite servicing, it may take a while for a freshly serviced regulator to ‘bed in,’ and it may require small adjustments.

Take the right tool for the job

Cold-water conditions are one of the leading reasons for regulator free-flows at depth. Regulator manufacturers produce cold-water rated regulators, specifically designed and tested to cope with tougher conditions. As the regulator’s first stage reduces air supply pressure from 3000psi (200 bar) to around 150psi (10 bar), the temperature inside the regulator drops. In cold water, this can cause the regulator to freeze, instigating a free-flow. So, if you’re planning to dive in colder or more challenging conditions, use a regulator that’s suitable for the task. Ensure your regulator is cold-water rated before you descend.

If you’re diving in a cold-water environment, note that fresh water is more likely to cause freezing and a free-flow than salt water. Pay close attention if you’re diving a freshwater lake or river. Try to keep your regulator free from moisture pre-dive to avoid any freezing in the cold air, and take exploratory breaths with the regulator submerged where it’s less prone to freezing. Finally, avoid big bursts of gas from your regulator when possible, such as using it to inflate a lift bag or deploy an SMB. These may cause a rapid temperature drop that could instigate a free-flow.

Beneath the surface

If, despite using a well-serviced unit suitable for the conditions, your regulator free-flows at depth, what should you do?

  1. Breathe

    As in any critical situation, stay calm and stop, think, breathe, and act. Both PADI and SSI teach the technique for breathing from a free-flowing regulator in their core Open Water Diver training for this very reason.Think back to your basic training and consider the key steps:

* Tilt the mouthpiece of the regulator’s second stage so that it’s partially in your mouth, gripped on the right side of your mouth as normal, left side resting on your lips just outside of your mouth.

* Angle your head or lean to the right. This allows you a clearer vision past the bubbles and helps you locate your buddy. It also means that (on a standard recreational scuba system) you’re correctly positioned to sweep and recover your regulator if the bubbles jolt it out of your hand.

* Keep your mouth slightly open and sip cautious breaths from the free- flowing air bubbling next to your mouth, using your tongue as a splash guard if necessary.

If you’ve been diving in suitably close formation, you should have ample time to locate your buddy. You can share air as you learned in your basic training and abort the dive before the situation becomes critical.

  1. Bail out 

    Many divers take a redundant air source, such as a stage-bottle or pony-bottle on more challenging or deeper dives. Having an additional, separate tank and regulator offers a solution to the free-flowing regulator situation that doesn’t necessitate immediately locating your buddy. Carrying a clipped-on stage-bottle or having a pony-bottle banded to your tank means you can solve the immediate issue independently. Simply swap to the back-up tank and then decide what to do next.

  2. Isolate 

    The ultimate solution to ensure a large gas reserve, redundancy and time to deal with your free-flowing regulator would be to use a double-tank twin-set. A twin-tank, twin-regulator set up with a manifold allows you to identify which regulator is causing the problem. Then you can isolate it by manually closing the manifold between tanks, and swapping to the functioning tank and regulator. You’ll want further training if you’re planning on using twin-sets, so consult your local dive center. PADI also offers a Self-Reliant Diver course, which features training in being more self-sufficient in the event of a problem.

You can practice all the above in-water skills in the pool. If you’ve not been through them recently, refresh yourself before your next dive trip. Book a pool session at your local center and practice with your buddy. Alternatively, book a review session with an experienced Divemaster or Instructor. They can walk you through the key steps if your regulator free-flows at depth.

A free-flowing regulator is an inconvenience that you can largely avoid or deal with safely. Take care of your regulators; take precautions when diving in challenging conditions; and become familiar with the key training and procedures in the event of an emergency, and you’ll have a much safer, more relaxed dive.

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