MSA Sirius Mode D'emploi page 70

5. Gently lift out and properly discard the sensor to be replaced.
• Use a flat-blade screwdriver to pry the CO and/or H 2 S sensors
from their holders.
6. For the combustible and/or O 2 sensor, carefully align the new
sensor pins with the appropriate sockets on the (lower) printed
circuit board. Press gently into position.
• If a combustible and/or an O 2 sensor is not to be installed,
ensure that the appropriate opening in the sensor gasket is
sealed with a sensor cover label (tape disc) (P/N 710487).
NOTE: If a Long Term O 2 sensor is being installed, remove and discard
circuit board connected to its pins before installation.
7. For the CO and/or H 2 S sensors, carefully press them into their
appropriate socket.
• The CO sensor has a filter disc attached to it. Be careful not to
damage the filter disk during handling and installation. Be sure
the filter disk is facing upward when installed.
• The H 2 S sensor is marked "H 2 S" on its top side; ensure that
the "H 2 S" mark and gas inlet hole face upward when installed.
• If a CO and/or an H 2 S sensor is not to be installed, ensure that
an "inactive sensor plug" (P/N 10046292) is installed properly
in its place.
NOTE: The CO and H 2 S sensor positions must not be swapped.
Verify that they are in the proper holder as indicated on the
(upper) printed circuit board.
Figure 6-8. Sensor Locations
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