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Murphy 100-500F Direct Mount Temperature Swichgage SDB500-2

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Murphy 100-500F Direct Mounting Temperature Swichgage with 1/2 NPT Thermowell - SDB500-2

Product Condition: NEW
Murphy Direct Mounting Temperature Swichgage 100-500°F with 1/2 NPT Thermowell and Sand-Cast Aluminum Case SDB500-2
Estimated ship date: for orders by 3pm PT/6pm ET today Available for back order.

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The Murphy SDB500-2 is a Direct Mounting Temperature Swichgage device that provides an accurate direct-reading gauge with an adjustable limit switch to activate alarms and/or shutdown. A knob on the front of the Swichgage allows you to adjust the limit switch trip point. Pointer movement is actuated by a bi-metallic sensing element. When the indicating pointer on the SDB500-2 touches the adjustable contact, a one-wire-to-ground circuit is completed to shut down the equipment and/or actuate audible or visual alarms. Proper relays or Tattletale annunciators (magnetic switches) must be incorporated into the system.

A thermowell (separable socket) is used to facilitate maintenance of a temperature Swichgage and to protect the temperature sensing bulb from extreme amounts of system pressure.

Applications: The most common use of the SDB Series is to monitor gas compressor temperatures. Engine exhaust temperature can also be monitored to indicate over-loading or lean fuel mixtures; or use the SDB to help coordinate loads on twin-engine installations.



  • Easy to Read Dial
  • Bi-Metallic Sensor
  • 100 to 500°F (40 to 260°C)
  • Dials Scaled in Degrees Fahrenheit/Celsius
  • Sand-Cast Aluminum
  • 1/2 NPT Thermowell



  • Part No.: SDB500-2
  • Temperature Ranges: 100 to 500°F (40 to 260°C)
  • Sensing Bulb Material and Size: 304 stainless steel; 1/2 in. dia. x 4 in. (13 x 102 mm) insertion depth
  • Maximum Bulb Pressure: 285 psi (1.97 MPa)[19.7 bar] at 625°F (329°C) NOTE: use of a thermowell is recommended
  • Process Connection: 1/2 NPTF
  • Sensing Element: High torque bi-metal element in heliarc welded stainless steel bulb
  • Contact Rating: 2 A @ 30 VAC
  • Limit Contact Adjustment: By knob through full range
  • Maximum Unit Temperature: 625°F(329°C)
  • Case Material: Sand-cast aluminum
  • Swichgage Accuracy: ± 3% of full scale
  • Wire: 18 AWG (1.0 mm2). See Dimensions for lengths (image #3), reverse side
  • Dial: Black print on stainless steel. Dials are scaled in degrees Fahrenheit and Celsius
  • Shipping Weight: 2 lb. (1.0 kg)
  • Shipping Dimensions: 8-1/4 x 4-1/4 x 4-1/2 in. (210 x 108 x 114 mm)


NOTE: All models are calibrated for use with a thermowell.

Additional Information

Product Condition NEW
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