Bypass Theory And Solutions

Bypass Theory

As Zone Dampers open and close, static pressure in the supply trunk can vary tremendously. Increasing static pressure increases air velocity and high velocity air can create objectionable air noise. Bypass is a technique used to maintain static pressure within acceptable limits. A trunk with a control damper is added between the supply and return. This provides an alternate path for some of the air if several supply dampers are closed.


Click on the layout image (above) for more layout information.

Bypasses should be designed to be as small as possible. Bypassed air is already conditioned therefore it interferes with heat transfer.

Bypass Damper Solutions

Young Regulator offers two bypass damper solutions:

  • The Barometric Counter-Balanced Damper

    The Barometric Dampers employ a weighted arm to balance static pressure. When zone dampers close and pressure increases to the point where it can overcome the weight of the counterweight, the damper will start to open. Barometric dampers are typically effective up to about 0.25" wc supply pressure.

  • The Electronic Bypass Damper
  • The Electronic Bypass Damper provides a finer level of control over a wider range of pressures. There is an on-board pressure switch to monitor static pressure. This modulates a damper to maintain particular setpoint. Round dampers feature an eliptical blade that provides a more proportional response.

Submittal Sheets

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Single-Point Zoning Brochure

Bypass Presentation Slides


Barometric Bypass Damper

Barometric Counter-Balanced Dampers
3095 (rect.) 4095 (round)

Electronic Bypass Damper.

Electronic Bypass System
3092 (rect.) 4092 (round)