User Guide

Zoning System Design Manual
11 70-2321—06
COMMERCIAL ZONING
Zoning for commercial buildings makes just as much sense as zoning for residential buildings: in a large office
building, each office suite could have its own zone, giving each occupant the ability to set the heat/cool to his or
her comfort.
Zone Design
While a typical residential building might have a system of 5 tons or less, commercial buildings typically have much
larger (up to 20 ton) HVAC units. A commercial zoning system will likely have more zones, and the ducts might be
bigger, but the basic principles of design and the devices used to implement zoning remain the same.
Pressure Relief Damper
The pressure relief damper may be a motorized damper such as the MARD, controlled by a static pressure control.
The MARD is then wired to a static pressure control (SPC) to modulate the bypass air.
Zone Damper
Zone dampers must be able to handle the higher airflow and static pressure of a larger HVAC system. Use a MARD
or RRD for round ducts. Honeywell Home doesn’t offer commercial-rated rectangular dampers. Commercial damp-
ers made by other companies can be used if they are powered by 24 volts AC. These could be either spring-open/
power-closed, or power-open/power-closed models. The zone panel sends a constant voltage to either open or
closed, so verify the damper used is compatible with constant voltage.