Trane LO manual Terminal Unit Control TUC, TUC Sequence of Operations

Terminal Unit Control (TUC)

The TUC is capable of operating in either a standalone application or interfacing with a Trane Tracer® system. In addition, Trane EveryWareä software is available to edit the configuration of the TUC.

The TUC board is easily access- ible on an isolation panel in the control panel. The TUC board will pivot down in the control panel box after removing the screw on the top right corner of the panel. See Figure 29.

TUC Sequence of Operations

Figure 29. The TUC module board.

Off: Fan is off; control valve options and fresh air damper options close. The low air temperature detection option is still active.

Auto: Fan speed control in the auto setting allows the modulating (three-wire floating point) control valve option and three-speed fan to work cooperatively to meet precise capacity requirements, while minimizing fan speed (motor/energy/acoustics) and valve position (pump energy/chilled water reset). As the capacity requirement increases at low fan speed, the water valve opens. When the low fan speed capacity switch point is reached, the fan switches to medium speed 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 will run continuously at the selected speed and the valve option will cycle to meet setpoint.

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