Trane International Inc.

William Randall Erwin

Bradley Thomas Wilson

Scott A Lackie

An air handling unit has an interior shell, an exterior skin associated with the interior shell to form a wall space at least partially bound by each of the interior shell and the exterior skin, and a control component at least partially carried within the wall space. A cabinet for an air handling unit has at least one wall comprising an interior shell and an exterior skin associated with the interior shell to form a wall space at least partially bound by each of the interior shell and the exterior skin. The at least one wall at least partially defines a fluid duct of the cabinet and a control component is at least partially disposed within the wall space.

Air handling unit with inner wall space

An HVAC switching circuit may comprise a current source circuit charging a capacitor used to power an HVAC DC power relay coil. The power relay coil terminal is connected to an activation control circuit which comprises at least one of (1) each of (a) a threshold circuit which activates a first transistor to energize the power relay coil when the voltage across the threshold circuit reaches a first threshold value and (b) a regenerative feedback circuit configured to lower the first threshold value to a second threshold voltage, and (2) a voltage divider connected between a first terminal on the power relay coil and the negative DC supply, and a programmable shunt regulator, configured as a level triggered switch, programmed by the voltage divider and connected between the second power relay coil terminal and the negative DC supply.

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Tyler, TX, United States of America

William Randall Erwin