Catalogue

50 UNT-PRC001-EN
Controls
Manual Output Test Function
NA on UC400. But will have ability through TU. This feature is an invaluable tool for
troubleshooting a unit. By simply pressing the controller’s test button, service personnel can
manually exercise outputs in a pre-defined sequence.
Peer to Peer Communication (Tracer ZN510, ZN520, and UC400)
Peer to peer communication allows multiple units in one space to share the same zone sensor and
provide simultaneous heating and cooling. The Tracer ZN510 or ZN520 controller can share
information between units on the same communication link using a twisted pair wire in the field.
Unit configuration must be modified with Rover service tool. On the UC400, zone sensor data
sharing can be accomplished by use of the BAS system controller.
Economizing Control (Tracer ZN520)
With the controller configured for economizing control, it will calculate the required cooling
capacity every ten seconds and modulate the damper option open to the calculated position. If the
setpoint is not satisfied, the damper will continue to open until the setpoint condition has been met
or the damper is 100 percent open. If this still does not satisfy the setpoint, the cooling valve option
will begin to open and try to satisfy the load requirements. Once capacity exceeds the load
requirements, the valve will begin to close until the setpoint has been reached or the damper
reaches its minimum position, which is field-adjustable. This option uses a three-wire, floating
point damper actuator.
A thermistor to sense discharge air is factory mounted near the discharge surface of the last coil
for use in economizing and cascade temperature control. Tracer Summit can also utilize this
temperature value as a read-only point. Cascade temperature control uses both the zone and
discharge air temperatures to more accurately calculate the required unit capacity.
A thermistor to sense fresh air is factory mounted at the unit’s fresh air opening for use in
economizer applications or as a read-only point for Tracer Summit. If the fresh air temperature is
a read-only value, it will not impact the control algorithm. In an economizer application, a fresh air
temperature signal must be provided either by this thermistor or Tracer Summit.
Control Features
UNT-PRC001-EN.book Page 50 Tuesday, May 8, 2012 10:54 AM