Trane Tracer ZN.520 Manual page 77

Sequence of operation
setpoint. The damper modulates between closed and minimum position when
the space temperature is 2–3ºF below the effective heating setpoint.
The modulating outdoor air damper normally is open to a minimum position
during the occupied mode when the controller turns on the unit fan. The
damper normally is closed during:
I Occupied mode when the fan is off
I Warm-up/cool-down mode
I Unoccupied mode
I Freeze avoidance
I Certain diagnostic conditions
This conforms to ASHRAE Cycle 2.
Cool-stand-alonedown
The controller keeps the modulating outdoor air damper closed (when the
controller is configured for modulating outdoor air damper control and an
outdoor air damper is present) for up to one hour at every transition from
unoccupied to occupied mode when the space temperature is three degrees or
more above the cooling setpoint.
The damper remains closed during cool-down until the space temperature is
within three degrees of the effective cooling setpoint. The damper normally is
closed during:
I Occupied mode when the fan is off
I Warm-up/cool-down mode
I Unoccupied mode
I Freeze avoidance
I Certain diagnostic conditions
This conforms to ASHRAE cycle 2.
The damper modulates between closed and minimum position when the space
temperature is 2–3ºF above the effective cooling setpoint.
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