Dual Temperature gauges
Dual Temperature gauges


  • Monitor inputs from two thermocouples
  • Adjustable switch trip point for each input
  • FET or SCR output
  • Power from CD ignition or 120 VAC or 12/24 VDC
  • Types “J” or “K” ungrounded thermocouples
  • Digital readings in Fahrenheit or Celsius



Murphy's model MDTM89 is an electronic, dual-temperature monitor. It monitors two thermocouples, displays the temperature of the thermocouple selected, and has adjustable trip points for each input. A toggle switch provides for selection of the thermocouple to be displayed and/or the temperature trip point to be checked/adjusted. If either trip point is reached, the associated output “turns on” and can be used as a control signal, or to initiate alarms and/or shutdown.


A “Push to Read” button, located below the selector switch, allows the operator to check the trip point and to see its value as adjustments are made. Two potentiometers, one on each side of the thermocouple selector switch, are provided for field-adjustment of the trip points. There are four basic models. Two of the models are powered by capacitor discharge ignition, and have either an FET or an SCR output. One model operates from 12 or 24 VDC and has an FET output. One model operates from 120 VAC by use of an isolation module and has an FET output. Standard display is in degrees Fahrenheit; degrees Celsius is optional.



  • Applications include the following:
  • Compressor suction/discharge temperature
  • Engine/compressor jacket water temperature
  • Engine exhaust temperature
  • Compressor cylinder temperature
  • After cooler temperature
  • Bearing temperature


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