Burner Air Register Opening Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 26, 2026Burner Air Register Opening Calculator
Turning a burner's air register halfway open does not deliver half the air flow - damper and register characteristics are curved, not linear, which trips up a lot of manual tuning attempts.
Formula: Q = Qmax × sin(90° × opening fraction)
At 50% opening, this gives sin(45°) = 0.707 - about 71% of maximum flow, not 50%. The curve is steepest through the middle of the travel range and flattens out near fully open, which is exactly why a small adjustment near the top of the range does much less than the same adjustment near the middle.
How to Use This Calculator
- Enter the register's maximum (fully open) air flow.
- Enter the current opening percentage.
Related: Burner Turndown Ratio Calculator.