Product Overview

VT8600 Rooftop, Heat Pump and Indoor Air Quality ControllerApplication Guide

028-6085-01 www.viconics.com | sales@viconics.com April 201

FRESH AIR DAMPER CONTROL SEQUENCES

The fresh air damper can be controlled through more than one sequence to achieve different control strategies such as free cooling

(economizer mode), minimum fresh air control and CO2 level control. Here are the control sequences available:

Note: For the sequences mentioned below, the following conditions must be met in order for the sequences to be performed as stated:

• Max Pos parameter value must be greater than Min Pos Parameter value.

• Mac CO2 parameter value must be greater than Min CO2 Parameter value.

• Max FA parameter value must be greater than Min FA Parameter value.

Economizer Control Mode Only

If the fresh air damper is to be used only for free cooling purposes (economizer mode, without fresh air measurement station or CO2

control), only the Min Pos parameter and the free cooling sequence will be active.

• The FA Range parameter should be set to 0 CFM. (Default Value = 0 CFM)

• Set the Chngstpt parameter to desired value which free cooling is enabled. (Default Value = 55°F)

If the outside air temperature is greater than the changeover setpoint, then normal mechanical cooling will be used. If the outside air

temperature is less than or equal to the changeover setpoint, then free cooling will be enabled and mechanical cooling stages will be locked

out.

Outside air sensor

BACnet MS/TP

Wired communication protocol

Control Board

Supply air sensor

Outside air

ZigBee

Pro

Optional wireless communication

Cooling coil Fan Heating coil

Return air

Supply air