Dwyer Series MP Mini-Photohelic® Differential Pressure Switch/Gage

 Dwyer Company Headquarters is in Michigan City, Indiana. Dwyer uses advances computer modeling software to simulate real world situations, creating more accurate measurement techniques in our products. Innovative product designs have been recognized by industry experts, including ACHR Dealer Design Awards in the Testing and Monitoring category for 2014 and 2015.

Dwyer has invested in state of the art research and development facilities for best in class product testing and verification. Dwyer has a long history of innovation in designing and manufacturing our own measurement sensors that provide superior product performance.

We work tirelessly to get it right. That's why Dwyer holds over 650 technical patents and that number grows every year. We are an enthusiastic group of people headquartered in Michigan City, Indiana with satellite locations around the globe. We take great pride in the intellect and integrity of our employees who are passionate about the work we do, the products we develop and the industries we serve.

Series MP Mini-Photohelic® Differential Pressure Switch/Gage

Known for quality, reliability and accuracy, Dwyer designs and manufactures a full-line of Controllers, Data Loggers, Gages, Manometers, Monitors, Remote Displays, Switches, Transmitters, and Accessories to measure, monitor and control pressure, air velocity, flow, fan pressure, duct, and more.

Dwyer’s wide selection extends to Gages, Transmitters, Switches, Data Loggers, and Monitors for Differential Pressure. Dwyer manufactures a range of dial and digital gages to reliably measure and display pressure difference, between two pressure sources using gas or liquid in a process flow.

Dial Gages and Switches are compatible with air and other non-combustible and non-corrosive gases. Dial Gages and Dial Switches are indicators for the difference between two pressures that also have switch outputs. They can also be used for single pressure.

The Series MP Mini-Photohelic® Differential Pressure Switch/Gage combines the time proven Minihelic® II differential pressure gage with two SPDT switching set points. The Mini-Photohelic® switch/gage is designed to measure and control positive, negative, or differential pressures consisting of non-combustible and non-corrosive gases. Gage reading is independent of switch operation. Switching status is visible by LED indicators located on the front and rear of the gage. Set points are adjusted with push buttons on the back of the unit.


  • Gage reading unaffected by switch operation and will continue to read pressure even during power loss
  • Visible switch status LED provides indication of set point switching state
  • Compact design but with the power of larger devices can meet the same application specifications


  • Fume hoods
  • Dust collection
  • Pneumatic conveying
  • Clean room

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Gage Specifications 
ServiceAir and non-combustible, compatible gases.
Wetted MaterialsConsult factory.
Accuracy±5% FS @ 70°F (21.1°C). Gage face mounted in vertical position.
Pressure Limits30 psig (2.067 bar).
Temperature Limits20 to 120°F (-6.7 to 49°C).
Process ConnectionsBarbed for 3/16" ID tubing (STD); 1/8" male NPT (optional).
Size4-1/8" (104.78 mm) depth x 3-1/16" (77.79 mm) diameter.
Weight23 oz (652 g).
Switch Specifications 
Switch TypeSPDT relays.
Electrical Rating5 A @ 120/240 VAC resistive; 5 A @ 30 VDC.
Electrical ConnectionsScrew type terminal block. Accepts 22-12 AWG wire.
Power Requirements24 VDC / 24 VAC 50/60 Hz 4 W.
Mounting OrientationGage face in vertical position.
Set Point AdjustmentPush buttons.
Standard Accessories(2) mounting screws, (1) .050" hex allen wrench.
Agency ApprovalsCE, cULus.

Download Data Sheet: Series MP Mini-Photohelic® Differential Pressure Switch/Gage

Ref: dwyer-inst.com