Speed adjustment of an actuator for an HVAC system

1. An actuator in an HVAC system, comprising:

a housing;

a motor;

a hub configured to receive a shaft;

an input connection configured to receive a first input signal for controlling operation of the actuator;

a user-operable mode selection switch attached to the housing and movable between a plurality of switch positions, each of the switch positions corresponding to a distinct operating mode, wherein the plurality of switch positions include a calibration position corresponding to a calibration mode; and

a processing circuit configured to control operation of the actuator using the first input signal, wherein moving the user-operable mode selection switch into the calibration position sends a second input signal to the processing circuit, wherein the processing circuit is further configured to temporarily shift the actuator from a first speed mode to a second speed mode that is faster than the first speed mode upon receiving the second input signal and to perform a calibration process with the actuator in the second speed mode, the calibration process comprising operating the actuator to drive the shaft through a predetermined sequence of positions with the actuator in the second speed mode, wherein performing the calibration process with the actuator in the second speed mode accomplishes the calibration process more quickly than if the calibration process were performed with the actuator in the first speed mode.

2. The actuator of claim 1 , wherein the user-operable mode selection switch is a potentiometer.

3. The actuator of claim 1 , wherein the processing circuit is configured to determine a position of the user-operable mode selection switch,

wherein the processing circuit is configured to temporarily shift the actuator from the first speed mode to the second speed mode in response to a determination that the user-operable mode selection switch has been moved through a predefined sequence of switch positions.

4. The actuator of claim 3 , wherein the predefined sequence of switch positions comprises moving the user-operable mode selection switch to a rightmost position and back to a leftmost position.

5. The actuator of claim 3 , wherein the predefined sequence of switch positions comprises moving the user-operable mode selection switch to a leftmost position and back to a rightmost position.

6. The actuator of claim 1 , wherein the processing circuit is configured to monitor the first input signal for an external override signal,

wherein the processing circuit is configured to temporarily shift the actuator from the first speed mode to the second speed mode in response to detecting the external override signal.

7. The actuator of claim 6 , wherein the override signal is a 24 VAC signal.

8. The actuator of claim 6 , wherein the override signal is from a controller.

9. The actuator of claim 8 , wherein the controller is a field controller.

10. The actuator of claim 8 , wherein the controller is a building management system controller.

11. The actuator of claim 1 , wherein the first input signal is sent without any physical adjustment of the actuator.

12. The actuator of claim 1 , wherein the processing circuit is configured to automatically perform the calibration process upon shifting the actuator from the first speed mode to the second speed mode.

13. The actuator of claim 1 , wherein the processing circuit is configured to automatically shift the actuator from the second speed mode back to the first speed mode upon completing the calibration process.

14. The actuator of claim 1 , wherein operating the actuator to drive the shaft through the predetermined sequence of positions comprises sequentially driving the shaft from an initial shaft position to at least one of a minimum shaft position and a maximum shaft position.

15. A method for temporarily changing the speed of an actuator for an HVAC system, the method comprising:

providing a processing circuit;

receiving, at the processing circuit, a first input signal for controlling operation of the actuator;

moving a user-operable mode selection switch of the actuator into a calibration position, wherein the user-operable mode selection switch is attached to the housing of the actuator and movable between a plurality of switch positions, each of the switch positions corresponding to a distinct operating mode, the calibration position corresponding to a calibration mode;

detecting, with the processing circuit, a second input signal, wherein the second input signal is sent to the processing circuit in response to moving the user-operable mode selection switch into the calibration position;

changing the speed of the actuator from a first speed mode to a second speed mode in response to detecting the second input signal, the second speed mode having a different speed than the first speed mode; and

performing a calibration process with the actuator in the second speed mode, the calibration process comprising moving the actuator through a predetermined sequence of positions with the actuator in the second speed mode.

16. The method of claim 15 , further comprising automatically changing the speed of the actuator back to the first speed mode after a predetermined sequence of events.

17. The method of claim 16 , wherein the predetermined sequence of events comprises performing the calibration process.

18. The method of claim 16 , wherein the predetermined sequence of events comprises removing the first or second input signal.

19. The method of claim 15 , wherein the second input signal is from the user-operable mode selection switch of the actuator.

20. The method of claim 15 , wherein the first input signal is an override signal from a controller.