Honeywell 1" x 3" Sail Sail Switch, SPDT

The S637 Sail Switches respond to the air velocity in heating or warm air ducts, such as used in farm crop dryers. The switch completes a 24V or line voltage burner control circuit only when the blower or fan has produced a predetermined air velocity. Features Micro Switch SPDT snap switch is operated by metal sail inserted in an air stream. Has a set of normally closed contacts which can be used to energize a signal or warning circuit when the velocity drops off. Sail can trimmed to one-half the original size to double the velocity required to close the snap switch contacts. Switch differential can be manually adjusted by turning a knurled knob on the snap switch. A conduit knockout is located on each end of the case for wiring convenience.