Dissolved Oxygen Sensor Troubleshooting Guide

Troubleshooting guides for equipment and Dissolved Oxygen Sensors are listed below. If you can’t find what you’re looking for, please Contact Us


Troubleshooting Equipment

The following tools are recommended to assist you in problem identification:

  • A DVM (Digital Volt Meter)
    A DVM is used to read mV or mA output from DO sensor in air or zero solution.
  • Handheld DO meter
    A handheld DO meter is useful as a comparative measurement to the readings from the sensor in question.
  • DO Sensor Maintenance Kit
    Use kit to replace membrane and electrolyte of your Sensorex DO sensor. Be sure and order kit based on membrane type (PTFE vs. HDPE) and DO sensor part number (since DO1200 has preassembled cap and membrane).

Dissolved Oxygen (DO) Sensor Troubleshooting

Check electrode in conductivity calibration/standard solutions as recommended above. Compare results to those on the following table:

DO Sensor output/SymptomPossible CauseCorrective Action
No outputa) DO sensor not connected to instrument
b) Bad connection at connector
c) Break in cable or internal connection broken in sensor
a) Check all connections from electrode to instrument
b) Check for electrical continuity from conductivity pin to connector using Ohms setting on DVM (should be <1 Ohm)
c) Contact Sensorex
Submersible probe output does not match handheld DO meter outputa) Probes not calibrateda) Calibrate both probes before comparing outputs
DO reading is unstable and drifts downwardElectrolyte depletedReplacement membrane and electrolyte per product instructions