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Apprentice Q&A · #078

What's the correct way to set a manual balancing damper quadrant so it doesn't rattle?

2nd YearDampersRED · Stop / Verify

Slide the regulator handle quadrant over the square damper shaft. Tighten the central locking wing-nut or hex bolt firmly down against the flat spot of the shaft. * Try to shake the handle with your hand; if there is any play, slap a backup locking washer on it. Loose dampers will vibrate at high frequencies under system air pressure, creating building-wide acoustic noise issues.

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Plain-English answer

Slide the regulator handle quadrant over the square damper shaft. Tighten the central locking wing-nut or hex bolt firmly down against the flat spot of the shaft. * Try to shake the handle with your hand; if there is any play, slap a backup locking washer on it. Loose dampers will vibrate at high frequencies under system air pressure, creating building-wide acoustic noise issues.

Field checklist

Ask Foreman

Hey boss, I’m on dampers and need verification before I touch this: What's the correct way to set a manual balancing damper quadrant so it doesn't rattle? Do you want me to stop here and check the approved detail, submittal, or inspector/manufacturer requirement first?

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Verify before acting

Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.

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