Uc400-B Stand-Alone Operation; Uc400-B Operation; Sequence Of Operation; Power-Up Sequence - Trane BCHE Installation, Operation And Maintenance Manual

Start-Up
When the fan switch is in the off position, the controller
does not control any unit capacity. The unit remains
powered and all outputs drive to the closed position. Upon
a loss of signal on the fan speed input, the controller
reports a diagnostic and reverts to using the default fan
speed.
ON/Cancel Buttons
Momentarily pressing the on button during unoccupied
mode places the controller in occupied bypass mode for
120 minutes. You can adjust the number of minutes in the
unit controller configuration using Rover service tool. The
controller remains in occupied bypass mode until the
override time expires or until you press the Cancel button.
Communication Jack
Use the RJ-11 communication as the connection point from
Rover service tool to the communication link—when the
communication jack is wired to the communication link at
the controller. By accessing the communication jack, you
can access any controller on the link.
Communications
The controller communicates via LonTalk protocol.
Typically, a communication link is applied between unit
controllers and a building automation system.
Communication also is possible via Rover, Trane's service
tool. Peer-to-peer communication across controllers is
possible even when a building automation system is not
present. You do not need to observe polarity for LonTalk
communication links.
The controller provides six 0.25-inch quick-connect
terminals for the communication link connections, as
follows:
• Two terminals for communication to the board.
• Two terminals for a connection from the zone sensor
back to the controller.
• Two terminals for communication from the board to the
next unit (daisy chain).
Table 35. Zone sensor wiring connections
TB1
Space temperature / timed override
1
2
3
4
5
6

UC400-B Stand-Alone Operation

The factory pre-programs the Tracer
default values to control the temperature and unit airflow.
®
Use Tracer SC building automation system or Tracer
106
Description
detection
Common
Setpoint
Fan mode
Communications
Communications
®
UC400-B with
®
TU
software to change the default values. For more
information, refer to Tracer
Controller for Blower Coil, Fan Coil, and Unit Ventilator
Installation, Operation, and Programming Guide BAS-
SVX48*-EN.
Follow the procedure below to operate the Tracer
B in a stand-alone operation:
1. Turn power on at the disconnect switch option.
2. Position the fan mode switch to either high, medium,
low, or the auto position.
3. Rotate the setpoint dial on the zone sensor module to
55°F for cooling or 85°F for heating.
The appropriate control valve will actuate assuming the
following conditions:
• Room temperature should be greater than 55°F and
less than 85°F.
• For a 2-pipe fan-coil unit with an automatic changeover
sensor, the water temperature input is appropriate for
the demand placed on the unit. For example, cooling
operation is requested and cold water (5° lower than
room temperature) flows into the unit.
• Select the correct temperature setpoint.
Note: Select and enable zone sensor temperature settings
to prevent freeze damage to unit.

UC400-B Operation

Controller
Off - Fan is off; control valves and fresh air damper option
close. Low air temperature detection option is still active.
Auto - Fan speed control in the auto setting allows the
modulating (3-wire floating point) or 2-position control valve
option and 1-, 2-, 3- or variable-speed fan to work
cooperatively to meet precise capacity requirement, while
minimizing fan speed (motor/energy/acoustics) and valve
position (pump energy, chilled water reset). As the capacity
requirement increases, the water valve opens. When the
fan speed capacity switch points are reached, the fan
speed ramps up and the water valve repositions to
maintain an equivalent capacity. The reverse sequence
takes place with a decrease in required capacity.
Low/Med/High - The fan runs continuously at the selected
speed and the valve option will cycle to meet setpoint.

Sequence of Operation

Power-Up Sequence

When 24 Vac power is initially applied to the controller, the
following sequence occurs:
1. The Power Marquee LED turns on as red, then flashes
green, and then turns a solid green.
2. All outputs are controlled OFF and all modulating
valves and dampers close.
®
UC400-B Programmable
®
UC400-
BCX-SVX002A-EN