Is your valve drill correct?

We see it every time a new tech student shows up for their first doubles checkout dive. They’ve watched the videos. They know the sequence. They reach back, locate the valve, and close it all the way down. Then open it back up.

Except they don’t. They open it back up one turn. Or a turn and a half. Or they lose count entirely and guess.

The Correct Valve Shutdown Sequence on a Standard Doubles Manifold

1. Right post valve — Close it fully, then breathe the right second stage down until the reg stops delivering gas. That confirms the right cylinder is off. Switch to your alternate and clip off your primary. Open the right post back up fully.
2. Isolator valve (center) — Close it fully. Open the isolator back up fully.
3. Left post valve — Close it fully, then breathe the left second stage down until it stops delivering gas. That confirms the left cylinder is off. Unclip and switch back to your primary. Open the left post back up fully.

Each valve gets closed, functionally verified by breathing the downstream reg to failure, then reopened. You’re not just cycling valves — you’re confirming that each cylinder and regulator is working correctly.

Failure Modes We Still See

• Skipping the reg breath-down — closing and reopening without verifying the second stage is theater, not a drill
• Not counting turns on close or open — partial closure restricts flow under high demand at depth
• Rushing the sequence — valve drills done slowly in a pool don’t automatically transfer to 100 feet with a free-flowing reg. You need the muscle memory, not just the knowledge.

The standard we hold in our TDI courses: every valve manipulated, every reg verified, every time.

That’s not perfectionism. That’s the baseline.

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Kraken DiveWorks | Newington, CT