Diffuser is whistling after startup
Whistling usually points to pressure/turbulence at a diffuser, damper, tap, sharp edge, or restriction. Find the source before closing dampers blindly.
Watch out Do not hide noise by cranking a damper shut without finding the restriction. Check Listen for exact whistle location. Check diffuser neck, damper position, collar, tap edge, and nearby elbow. Look for takeoff too close to a fitting. Document condition with room/device tag. Ask before cutting, relocating, or changing damper setting. Steps Listen for exact whistle location. Check diffuser neck, damper position, collar, tap edge, and nearby elbow. Look for takeoff too close to a fitting. Document condition with room/device tag. Ask before cutting, relocating, or changing damper setting. Say this to your foreman The whistle is at [device/location]. Do you want me to check diffuser neck, damper, tap, and takeoff location before we change anything?
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