Honeywell #S688A1007, Sail Switch with 5 in. wide sail

The Sail Switch activates an electronic air cleaner, a humidifier, or other equipment in response to airflow from the system fan. The S688A is mounted in the return air duct where the sail will be in the direct path of an unrestricted air stream.

Features
Simplified installations with multi-speed fans, in- accessible air handlers, fan motors with voltage or phase different from controlled equipment; eliminated wiring to system fan.
Polyester film sail mounted on a micro switch snap switch.
Removable spring counterbalances sail to allow mounting in either vertical (up or down) or horizontal air flow.
Top and bottom conduit knockouts for wiring convenience.
Low air velocity switch operation makes at 250 fpm and breaks at 75 fpm.