Application Note: Controlling an AAON VCCX2 with 75F

Use Case:

AAON units are often selected with the AAON VCCX2 controller.  The VCCX2 does allow hardwiring of Occupancy Enable and Discharge Air Temperature Setpoint, but in applications where there are multiple CCUs controlling zones that are served by this unit, this strategy does not work.

Solution:

The VCCX2 is a devices that communicates via BACNet.  With the use of a 75F Jace/AHU Control Panel, we are able to leverage the sequences that the CCUs provide to optimize the AHU and ensure the unit operation is in sync with the VAV Zones.  The VCCX2 will provide the control of the unit, while 75F provides Occupancy Enable, HVAC Mode, Discharge Air Temp Setpoint, and Duct Static Pressure Setpoint based on ASHRAE Guildeline 36 via the following VCCX2 BACNet points:

AV55 - Duct Static Pressure Setpoint

AV67 - Occupancy Override

AV68 - HVAC Mode (Heat or Cool)

AV71 - Supply Air Temperature Setpoint