Calibration and Bump Test Sequence for H2S and ClO2

When calibrating devices, the presence of Hydrogen Sulfide (H2S) will cause the Chlorine Dioxide (CIO2) response to show an OL then UL error.

Blackline manufacturing uses a Chloride Dioxide electrolytic generator as the source for CIO2 calibration gas. The recommended balance gas for the single H2S source is either nitrogen or a synthetic air blend.


To calibrate your sensor effectively when both H2S and CIO2 are being sampled, perform the following steps.

  1. Using a single gas calibration cap (ACC-S-CAL), calibrate the ClO2
  2. Using a quad-gas calibration cap (ACC-Q-CAL), calibrate the H2S sensor.
  3. After calibration is complete, apply a burst of ClO2 gas directly to the ClO2 sensor for 5 to 10 seconds.

    The burst of ClO2 after the H2S will help purge the remaining H2S from the ClO2 sensor and allow the device to detect gas normally.

Bump Test

To bump the H2S and ClO2 sensor combination when a ClO2 generator is unavailable on-site, perform the bump test on the H2S sensor using either the single H2S gas or the standard quad-gas mixture. There is a known cross sensitivity between the quad-gas CO and H2S.

If you do not have a ClO2 generator and would like to calibrate or bump test the ClO2 sensor, contact Blackline Customer Care for additional information on ClO2 electrolytic cells.