Free Flow — What It Is and Why It Matters
A free flow is a regulator malfunction where the second stage delivers air continuously rather than only on demand. The valve mechanism fails in the open position, sending a constant stream of air from the tank. While you can still breathe from a free-flowing regulator (by sipping air from the constant flow), it rapidly depletes your air supply.
Free flows are most commonly caused by cold water (ice forming on the valve mechanism), a damaged or contaminated valve seat, or debris in the second stage. In cold water, free flows can cascade — the rushing air cools the mechanism further, causing more icing and worsening the flow. Environmentally sealed first stages and cold-water rated regulators reduce this risk.
Frequently Asked Questions
Can I breathe from a free-flowing regulator?
Yes. Do not seal your lips around the mouthpiece — instead, hold it loosely against your mouth and sip the air from the continuous flow. This technique lets you breathe while preventing your lungs from over-pressurizing. Begin your ascent immediately, as your air supply is being rapidly depleted.
What causes a regulator to free flow?
The most common cause is cold water — below about 4°C (40°F) — where ice crystals form on the valve seat. Other causes include a worn or cracked valve seat, debris in the mechanism, or an improperly adjusted cracking pressure. Regular servicing significantly reduces free flow risk.
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