where to add turn on/off DCV on IES?

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All prototype systems in ApHVAC do not have the controllers required for DCV. Either start with a system that has DCV built in or you have to go steal the components and add them to your system. System 5b and the DOAS systems all have the controls necessary for DCV. The ApHVAC user guide has some examples on how to add DCV to some of the most commonly used systems (https://help.iesve.com/ve2018/prototy...).