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).

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

DO Sensor output/Symptom	Possible Cause	Corrective Action
No output	a) 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 output	a) Probes not calibrated	a) Calibrate both probes before comparing outputs
DO reading is unstable and drifts downward	Electrolyte depleted	Replacement membrane and electrolyte per product instructions