Model 717A

SKU: 717A

Displacer Switch, Top Inserted, Three Point

Operation: The weight of a displacer is supported by a spring. Variations in liquid level cause the displacer to move up and down. Switching action occurs as the level passes each displacer.

Uses: High and/or low alarm; single and multiple pump control

Insertion and Switching band: up to 50 feet maximum

Switch action: From 1 to 4 points of alarm and/or on-off pump control

Specific Gravity: form 0.25 to 2.4 SGU

Temperature: from –20 to 500°F

Pressure: from –15 to 2200 PSIG

Process Connection: 3″ to 4″ NPT threaded; 3″ to 12″ flanged up to 1500# rating; ASA, DIN, or JIS style

The Delta Controls Model 717A is very similar to the Model 716 displacer switch, which has only 2 alarm points. The major difference is that the stroking distance has been increased and a third switching station and displacer have been added.


A precise on/off action occurs in the appropriate switch station when the liquid level surface passes the elevation of the related displacer element.

The Delta Controls Model 717A is commonly used to control two pumps acting to empty a sump. Each of the two top displacers starts a pump; the lower displacer operates a DPDT switch, which acts to stop both pumps at the same place. Latch/unlatch pump starters are normally used in this arrangement.

Model 717A Product Diagram - Delta Controls Corporation

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