Static field route #1014

The duct run vibrates or rattles when the air handler starts

Airflow, Noise, Vibration & TAB Impactsyellow

Treat startup vibration as a support/connection/TAB symptom. Check hangers, flex connector, joint tightness, equipment connection, isolation, and whether duct weight is being carried by the wrong part.

Open in Field Rescue Open category

Field checklist

Stand clear of moving/vibrating components.
Check if vibration starts at equipment or a loose duct section.
Look for missing support, long unsupported span, loose joint, flex connector stretched tight, or metal rubbing structure.
Photograph/video the symptom and location.
Ask before adding random screws/bracing.

Ask foreman

When the AHU starts, this duct vibrates/rattles at [location]. I checked supports and equipment connection. Do you want me to inspect hangers, joint fit-up, or flex connector first?

Do not

Do not grab vibrating duct, wedge random material into supports, or silence the symptom without finding the cause.

Why it matters

Noise/vibration after startup often points to support, fit-up, isolation, or airflow problems that matter to TAB and owner comfort.

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