SC-04
Chapter 6: Maintenance • 67
Replacing the Sensor Filter
NO
2
and SO
2
Sensors’ Filter: The H
2
S filter disk is tan in color. The filter should be replaced
every 6 months.
HCN Sensor Filter: The H
2
S filter disk is dark gray in color. The filter should be replaced
every 6 months.
PH
3
Sensor Filter: The humidity filter disk is white in color. The filter should be replaced
every 6 months.
NH
3
Sensor Filter: The humidity filter is white in color. The filter should be replaced every 6
months.
1. Verify that the SC-04 is off.
2. Remove the rubber boot, if installed.
3. Use a small Phillips screwdriver to unscrew the 4 screws that attached the front case to the
rear case.
4. Turn the instrument right side up. The screws are not captive and may fall out. Be sure not
to lose them.
5. Remove the front case from the rear case.
6. Turn the front case upside down.
7. If the sensor stayed in the front case, remove the sensor.
Figure 11: Unscrewing Case Screws
Screw, 4x
Front Case
Rear Case
Figure 12: Case Separation