Applications Guide Tracer Graphical Programming - Trane

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Chapter 6 VAV AHU example
Figure 112: Discharge air control program properties
Controlling the mixed air and outdoor air damper
Operation of the outdoor air damper and subsequent mixed air temperature
control must satisfy a number of scenarios according to the sequence
of operation.
Modulate the outdoor air damper between the adjustable minimum position
and fully open to maintain the discharge air cooling setpoint when
all of the following are true:
• The economizer is enabled.
• The outdoor air temperature is less than the economizer changeover
(or outdoor air temperature) setpoint.
• The air handler is in cooling mode.
Modulate the outdoor air damper closed, overriding the minimum position,
to maintain the mixed air temperature at or above the mixed air setpoint.
Control the outdoor air damper to its minimum position when either of
the following is true:
• The economizer function is disabled.
• The air handler is in heating mode.
120 CNT-APG001-EN