Purpose and Applicable Part/Model Numbers


This document describes issues related to firmware mismatches in the H2 Zero unit..

  • 016-551-10 H2 Zero, Main Unit
  • 016-552-10 H2 Zero, Remote Hydrogen/Temperature Sensor
  • 016-553-10 H2 Zero, Control Module

  • Troubleshooting Steps 

    Fan Control Board Firmware Mismatch

    If the fan control board and the main control board are both not programmed with the most current firmware, the unit can enter a condition in which the fan unit will stay on continually.


    Check the firmware version of the control board, if it is not r05 turn the controller off and this should turn the fan off. If the fan shuts off, then mismatched firmware is the issue. If this is is the issue then the controller board will need to be swapped for a current board.

    Please contact Comm/net Systems Support for RMA (Return Merchandise Authorization) instructions.

    If you are experiencing problems, please contact Comm/net Systems Support


    Comm/net Systems Inc. Support


    (206) 282-8670

    or submit a support ticket through this portal.