Barometric damper

[MustangP44]

I just installed a 3 zone board on a 3 ton unit with three equal 1 ton zones. I did the set up with the damper, with all three zones calling for full CFM. Unfortunately, even after the set up was complete when only one zone is calling the damper will not open fully and I get excessive airflow. If I manually open the bypass damper fully, I get the desired airflow on any of the 1 ton zones. I’ve performed the set up again and I am still getting the same results. Why won’t my barometric damper open 100% to maintain the proper static when only one zone is calling?

[Paul Z.]

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