Model 717

SKU: 717

Displacer Switch, Top Inserted, Three Point

The Delta Controls Model 717 Displacer Switch has three alarm points, three switching stations and three displacers. A precise on/off action occurs in the appropriate switch station when the liquid level surface passes the elevation of the related displacer element.

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 717D utilizes an adjustable differential device has been added, and only two switch stations are utilized. The lower switch station is activated when the liquid surface covers the middle displacer and stays activated until the liquid level falls below the bottom displacer. A typical application is to control a single pump with a high or low level alarm.


  • Top inserted
  • Three alarm points
  • Three switching station displacers
  • Displacer weight is supported by a spring
  • High and/or low alarm
  • Single and multiple pump control


  • Wetted Materials: 3316 Stainless Steel, carbon steel
  • Insertion (Below Process Connection): ≤ 50 ft max
  • Switch Action: 3 alarm points and/or differential
  • Specific Gravity: 0.55 to 1.45
  • Temperature Range:-20 °F to +500 °F (-29 °C to +260 °C)
  • Pressure Range: -15 psig to +2200 psig (1 bar to +151.6 bar)
  • Threaded Process Connection:3.0 in to 8.0 in NPT
  • Flanged Process Connection:3.0 in to 12 in
  • Flange Rating: ≤ 300 lb ANSI flanges or Grayloc® hub DIN or JIS equivalents

Certifications & Approvals

  • Third Party Listed by CSA NRTL/C (USA and Canada)
    Class I, Division 1, Groups B, C and D;
    Class II, Division 1, Groups E, F and G;
    Class III, Division 1
    Class I, Zone 1, Ex d IIB+H2
    Class I, Zone 1, AEx d IIB+H2

Required Ordering Information

  • Detailed model number
  • Tag or nameplate detail (if required)
  • Documentation/testing tiers (if required, refer to Additional Resources in the product catalog)
  • Process fluid or material name*
  • Process fluid or material specific gravity
  • Maximum process temperature
  • Maximum process pressure

Additional Information


Displacer Switch, Top Inserted, Three Point

Level Measurement


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