Trane Tracer ZN511 User Manual page 7

Automatic ventilation reset
Because ensuring proper ventilation
rates is so important for indoor air
quality, the Tracer ZN521 is configured
with two outside/fresh air damper
minimum position setpoints for
occupied operation. As the fan speed
changes, the damper minimum position
changes to maintain the correct
ventilation rate.
Fan status
The Tracer ZN521 has two methods of
monitoring fan status. The first method
monitors the fan output status on the
unit controller. This method is typically
used with direct fan applications.
The controller can also accept a binary
input from a fan proof switch for belt
driven applications. When fan operation
is expected by the controller but not
confirmed by the proof switch, a
diagnostic message is generated and
unit operation is disabled.
Filter maintenance
Filter maintenance status is based on
the cumulative hours of operation of the
unit fan. The controller has timers that
can be reset, and when the time limit
expires, Tracer Summit software or the
Rover service tool indicates that unit
maintenance is recommended.
BAS-PRC006-EN
Water valve override
This function causes all of the water
valves in every unit to open
simultaneously at a command from
Tracer Summit software or the Rover
service tool. This function reduces the
time required for balancing the water
distribution system.
Relative humidity input
An analog input can be configured as a
relative humidity input. The controller
can use this value to support the
dehumidification function.
Active dehumidification
This feature keeps relative humidity
levels within ASHRAE 62-89R guidelines
to maximize comfort and minimize the
risk of microbial growth and damage to
the building or furnishings due to
humidity. The controller can provide
active dehumidification when the
equipment includes a reheat coil and a
humidity sensor.
CO input
2
An analog input can be configured to
measure CO . Tracer Summit can use
2
the input in a variety of applications. This
input has no direct effect on the
operation of the controller.
Two-stage electric heat
The Tracer ZN521 supports 1- or 2-stage
electric heat operation for heating. To
control the zone temperature, electric
heat is cycled to control the discharge air
temperature. The rate of cycling is
dependent on the load in the space and
the temperature of any incoming fresh
air from the economizer.
Two-pipe changeover units with electric
heat use electric heat when hot water is
not available.
Economizing control
When the Tracer ZN521 is configured for
economizing control, it opens the
outdoor damper to the calculated
position to provide "free" cooling as
required. If the damper is completely
open and the setpoint is still not
achieved, the cooling valve opens to
satisfy load requirements. As cooling
load requirements decrease, the valve
closes until the setpoint is reached or
the damper reaches its adjustable
minimum position.
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