Trane LO Manual, Auto 2-Position Economizer, Terminal Unit Control TUC, Fresh Air Damper Options

Terminal Unit

Control (TUC)

Note: The auxiliary electric heat option is not available with a four-pipe fan-coil unit.

Fresh Air Damper Options

Manual

Units with manual fresh air dampers ship with the damper in the closed position, which is adjustable from zero to 100 percent in 25 percent incre- ments. To adjust the position, first remove the air filter to expose the damper stop screw on the control panel end. Relo- cate the stop screw to the appropriate position. Then loosen the stop screw wingnut and adjust the linkage. See Figure 30.

Figure 30. Re-locate the damper stop screw to adjust the damper position. The factory positions the stop screw in the 25% open position.

Auto 2-Position

Economizer

Units with an auto 2-position fresh air damper ship with a stop screw in the 25 percent reference position. The auto damper is adjustable to open from zero to 50 percent in 25 percent increments. To adjust the damper position, remove the air filter to expose the damper stop screw on the control panel end. Then relocate the stop screw to the appropriate position. See Figure 30.

Note: The open position of the damper does not correspond to the amount of fresh air. It is the installer’s responsibility to ensure that the building’s minimum fresh air requirements are met while taking necessary precautions to protect the unit during freeze conditions.

The economizer damper option contains a modulating, 3-wire floating point actuator and a damper assembly. The factory sets the damper at a minimum 25 percent open position by configuring the TUC. This setting is adjustable and can be changed in the field with EveryWareä software or Tracerâ. The minimum open position is adjustable from zero to 100 percent in one percent increments.

The economizer fresh air damper is controlled to the minimum position, which the factory configures. During the occupied mode, economizing is enabled and the fresh air temperature is measured while economizing.

Economizing is enabled within the TUC configuration based on an editable temperature differential between the fresh air temperature and the zone temperature. The unit will go into economizing mode when

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