Trane Tracer UC400 User Manual

BAS-SVX48H-EN
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UI2; Outdoor Air Temperature
If UI2 is configured as the local (hard wired) outdoor air temperature input, the UC400 Controller
receives the temperature as a resistance signal from a 10 kΩ thermistor wired to UI2. An outdoor
air temperature value communicated by means of a BACnet link, can be used for controllers
operating on a BAS. If both hard wired and communicated outdoor air temperature values are
present, and in service, the controller uses the communicated value. If a valid hard wired or
communicated outdoor air temperature value is established, and then is no longer present, the
controller generates an Outdoor Air Temperature Failure alarm.
The economizing (free cooling) function uses outdoor air is used as a source of cooling before
using hydronic or DX cooling. The controller uses the outdoor air temperature value to
determine whether economizing is feasible. Economizing is not possible without a valid outdoor
air temperature. The outdoor air temperature value is used for the freeze avoidance function.
This function is used for low coil temperature protection when the fan is OFF. The controller
enters the freeze avoidance mode when the outdoor air temperature is below the freeze
avoidance setpoint (configured using the Tracer TU service tool).
Binary Outputs
The UC400 includes nine (9) binary outputs. BO1, BO2, and BO3 are relay outputs and BO4
through BO9 are TRIAC outputs.
IImmppoorrttaanntt:: 24 Vac must be provided to the TRIAC supply input.
The UC400 supports the following blower coil, fan coil, and unit ventilator applications:
• Supply fan with 1-, 2-, or 3–speed or variable speeds.
• Face/bypass damper for some hydronic Unit Ventilator applications.
• DX cooling single- or dual-stage.
• Electric heat single stage, two stage, or modulating.
• A 2-position or 3-wire floating point modulating outdoor/return air damper.
Override Outputs
Analog and multi-state value request points are included in order to safely override outputs
without disrupting TGP2 program operation. To override valves and dampers for commissioning
or testing purposes, access the following points on the Analog or Multi-state tabs of the Tracer
TU service tool :
• CCooooll VVaallvvee RReeqquueesstt:: analog value point for 2-position and modulating hydronic cooling and
changeover valve.
• DDXX CCooooll RReeqquueesstt:: analog value point for 1- and 2-stage DX cooling and heat pump.
• HHeeaatt VVaallvvee RReeqquueesstt:: analog value point for 2-position and modulating hydronic heating
valve.
• EElleeccttrriicc HHeeaatt RReeqquueesstt:: analog value point for modulating, 1- and 2-stage electric heating.
• EEccoonnoommiizzeerr RReeqquueesstt:: analog value point for 2-position and modulating outdoor air damper.
• SSuuppppllyy FFaann SSppeeeedd RReeqquueesstt:: analog value point for variable speed (0-100%) fan applications,
including Trane ECM engine module.
• SSuuppppllyy FFaann SSppeeeedd BBAASS:: multi-state value point for fixed 1-, 2-, and 3-speed fan.
Wiring Requirements
The following table lists the required UC400 Controller inputs for minimum proper operation of
all applications. The following wiring diagrams are separated to show first the UC400 and then
the UC400–B
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Trane Tracer UC400 Specifications

General

Brand	Trane
Model	Tracer UC400
Category	Controller
Language	English