DFS Series
Air Pressure Sensing Switches

DFS-221
Model DFS–221 is an airflow proving switch designed for duct heater, oven, and other HVAC or Energy Management applications where an open-mounted, nonadjustable switch is desirable. It is especially suitable for surface-mounting in areas where internal access is limited. It can be used to sense positive, negative, or differential air pressure.

The DFS–221 is equipped with two convenient sample line connectors (1⁄4″ OD slip-on fittings) that accept flexible tubing.

The plated housing contains a diaphragm and a snap-acting SPDT switch. The sample line connections located on each side of the diaphragm accept flexible tubing. The electrical connection consists of male 1⁄4″ quick connect terminals.

The SPDT snap action switch operates on pressure rise of 0.05″w.c., ± 0.02″ w.c.

Additional DFS Series Products

DFS-448-112

DFS-448-112

DFS SeriesAir Pressure Sensing SwitchesModel DFS-448-112 Air Pressure Sensing Switch is a proving switch designed for...

DFS-301

DFS-301

DFS SeriesAir Pressure Sensing SwitchesModel DFS–301 is an airflow proving switch designed for duct heater, oven, and...

DFS-221-112

DFS-221-112

Model DFS-221-112 Air Pressure Sensing Switch is a proving switch designed for duct heater, oven, and other HVAC or Energy Management applications where an open-mounted, nonadjustable switch is desirable. It is especially suitable for surface-mounting in areas where internal access is limited. Model DFS-221-112 can be used to sense positive, negative, or differential air pressure. The plated housing contains a diaphragm and a snap-acting SPDT switch. The DFS- 221-112 is equipped with convenient dual- barbed sample line connectors located on each side of the diaphragm. The dual-barbed connectors accept 3⁄16″ or 1⁄4″ ID flexible tubing. The electrical connection consists of 1⁄4″ 90o quick connect spade terminals. The SPDT snap action switch operates on pressure rise of 0.05 ± 0.02″ w.c. For additional application and technical information, please contact the sales office.

DFS-221

DFS-221

DFS SeriesAir Pressure Sensing SwitchesModel DFS–221 is an airflow proving switch designed for duct heater, oven, and...

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