Are Bypass ducts needs in a Dual Zone System

Hi all,
I'm planning to have a Honeywell dual zone system nstalled in a two- story 2400 sq ft home. Their will be a thermostat on each floor. I've read that a bypass duct isn't required in this type of installation. Is this correct?
I recall seeing an episode of "Ask This Old House" where not having a bypass duct was the cause of some overpresure issues. Unfortunately, I don't recall the size of the home or the number of zones.
Thanking you in advance, Orlanzo
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So you want us to guess how this system is designed?
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You dont. When the zones start shutting down the ductwork just explodes. Your Welome in advance Bubba
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Dual zone "WHAT" heat pump, ac, furnce??????????
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AC and Furnance.
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