Keeping Vibration OFF THE WALL with Mini Split HVAC

The advent of ‘Mini-Split’ HVAC components in the heating & cooling of residential spaces has heightened the need for vibration isolation once again.  The economy of scale of these newer CAD designed units has given rise to a request from KELLETT to remove the vibration from these wall mounted ‘split’ units, wherein the internal component of the split unit is mounted directly to an interior wall section.

graphic for keeping vibration off the wall

Photo courtesy of Russ Hellem

Normally, these fan coupled units exhibit considerable vibration.  If left untreated when mounted to the wall, this machine unit vibration can easily be transferred to structural components, thus proffering structure borne noise.  In an effort to alleviate this encumbrance, KELLETT has been working with various manufacturers to implement a simple straightforward program of vibration isolation for both components of the Mini-Split System.

There are normally two components; the indoor fan coupled wall unit, and the outdoor ground set compressor unit.  These two typically produce both machine unit vibration & airborne sound.  Location of the outdoor component should be away from a ‘non sensitive’ wall of the structure, to minimize noise from fans to wall & windows.  Additionally, the outdoor component should be set on a level base, providing correct deflection rated vibration isolation pads.

KELLETT pads placed between the machine & the concrete base will minimize noise from normal operation  (published sound power data), as well as providing bi-directional constrained layer vibration damping, to increase machine unit reliability by reducing potentially damaging vibrations.

All piping penetrations through the outside wall should be overcut, to prevent piping from making hard contact with the wall framing & sheetrock.  Any gaps should then be sealed with a non-hardening sealant.  Air gaps may allow sound from the outdoor unit to more readily penetrate the existing wall structure.   It then becomes a straightforward matter to isolate the brackets of the interior ‘split’ wall unit from the wall, utilizing KELLET pads & KELLETT Bolt Isolator Kits, to minimize the transfer of vibration to the framing and sheetrock.  This simple two step process will reduce the Noise!

This entry was posted in noise and vibration isolation, Shock and Vibration Exchange, Shock Isolation, Vibration Isolation and tagged , . Bookmark the permalink.

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