resideo Powering a TrueZONE panel using the system transformer Installation Guide 
INSTALLATION ADDENDUM
This addendum is regarding the recommendation made in Resideo Zoning literature for the use of a dedicated transformer as part of a zoning system. This recommendation was made to simplify installation and ensure there is adequate power for the zone panel, dampers, and thermostats.
Resideo TrueZONE panels are approved to operate using any 24 VAC source, such as the HVAC transformer, provided there is adequate VA to power the panel, dampers, and thermostats, as well as any other equipment powered by that transformer.
If an Add-A-Zone panel is used with the HZ432 zone panel, the Add-A-Zone panel should be powered using a different transformer than the HZ432 zone panel.
When determining if there is adequate VA, remember that the ARD and ZD dampers are power closed and that the TrueZONE panels default dampers to open when no zones are calling. In this open state, ARD and ZD dampers are not drawing power. Because of this, when a single damper is used per zone, a two-zone system will see a maximum of one damper powered at a time and a three-zone system will see a maximum of two dampers powered at a time.
The current draw at 24 VAC of Resideo zone panels and dampers is as follows:
- HZ432 Zone Panel = 8.5VA
- HZ322 Zone Panel = 7.5VA
- HZ311 Zone Panel = 6.25VA
- HZ221 Zone Panel = 6.25VA
- ARD series Zone Damper = 8VA
- ZD series Zone Damper = 8VA
To determine how much VA the zoning system requires, add the panel and thermostat current draw plus the maximum number of dampers that can be closed at any one time and current draw of the damper. The current draw of thermostats varies by type and if the backlight is on. Do not add any VA if the thermostat is battery powered. Add 3VA for each hard-wired thermostat. Add 3VA if the thermostat uses an EIM (Equipment Interface Module) wired into the zone connections of the TrueZONE panel.
Example: On an HZ322 with two ARD or ZD series dampers, there is 7.5VA (Zone Panel) + 8VA (Damper) +6VA (thermostats) = 21.5VA required from the 24 VAC transformer to power the zoning system.
Then verify that the transformer has sufficient VA to handle this load in addition to any other equipment it is powering.
www.resido.comResideo Technologies, Inc. 1985 Douglas Drive North, Golden Valley, MN 55422 1-800-468-1502 33-00580EFS—01 M.S. 05-21 | Printed in United States.© 2021 Resideo Technologies, Inc. All rights reserved. This product is manufactured by Resideo Technologies, Inc. and its affiliates.
References
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