Clevland Controls PS221 AFS222121 General Purpose Air Switch

Supco AFS222121 General Purpose Air Switch

Features / Benefits

•  Senses positive, negative or differential air pressure.
•  Set Point Range: 0.05" to 12.0" w.c.
•  Electrical Ratings: 300 VA pilot duty @115 to 277 VAC, 15 amp non- inductive to 277 VAC, 60 Hz.
•  Contact Arrangement: SPDT
•  Operating Temperature: -40°F (-40°C) to 180°F (82°C).
•  UL & CSA Approved.
•  2-year warranty

Common HVAC&R Applications

•  On gas fired warm air furnaces, prove fan flow by sensing draft down from blower; switch actuation allows ignition start up or shuts system down upon insufficient draft.
•  Electronic air cleaners and humidifiers can employ sensing switches to prove airflow; switch actuation starts unit with sufficient airflow or draft.
•  Strip heaters employ airflow sensing switches to prove positive pressure/airflow in duct and air movement across heat source; shuts off heat source with insufficient airflow.
•  Exhaust fans and draft hoods employ sensing switches to sense draft down from exhaust fan; switch actuation signals condition upon fan failure or insufficient draft.
•  Refrigeration and cooling coils are maintained by sensing differential pressure/airflow drop across coils; switch actuation signals condition when they ice, or actuates the defrost cycle.