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In-Situ Oxygen and Combustibles (COe) Transmitter

Superior Design for Superior Results!

  • Combination of O2 and COe for ideal combustion efficiency
  • Real-time measurements
  • Unique, heated solid electrolyte combustibles sensor
  • Easy access to sensors for fast and simple service

The MRU OMS 420 Series Transmitters are offered in four different versions: Compact, Remote mount, High-temp, or Ex for hazardous locations.  The OMS 420’s are  the ideal choice to optimize fuel efficiency on combustion sources, with a number of advantages over other transmitters.

  • The addition of our unique combustibles sensor allows safe operation with a lower Excess Air Ration, translating in to higher efficiencies
  • The MRU Combustibles Sensor is accurate and stable even down to 1% oxygen – No dilution is needed.
  • The Flow Guidance Tube design allows the sensor to be mounted near the back of the transmitter to make service fast, easy, and no need for system shutdown.
  • Mounting versatility
  • Available Auto Calibration

Better sensors and design for better performance and reliability

  • Zirconium dioxide O2 sensor has long life, fast response, high stability & low energy consumption
  • Heated Solid Electrolyte COe sensor has high accuracy/sensitivity, fast response, long life, and stable down to 1% oxygen -No dilution air required,
  • Flow Guidance Tube allows easy access to the sensors and are suitable for high dust / particulate or high temperature applications to 3000°F with probe lengths to 6′
  • Optional Auto Calibration
Measuring ranges
COe – Combustibles 0 … 1,000 ppm COe (combustibles gas)
O2 – Oxygen 0.1 … 25 % (user defined analog output range)
Dimensions and other data
Transmitter outputs Two (2) 4/20mA and RS485 (Modbus)
Flange DN65 PN6, Ø 6.5″ (165 mm) for Compact & RT

4″ 150lb ANSI for HT;

4″ 150lb ANSI Flange Adapter for Compact & RT


Response time T90 < 10 seconds
Power supply 18-24VDC; 90-100 W
Protection class IP 65
Weight > 33lbs (15 kg), depending on probe tube size
Download File type File size
OMS 420 Brochure
PDF 666 KB
OMS 420 Selection Chart PDF 231 KB Download
OMS 420 Questionnaire
DOC 100 KB Download