14 • 65-2427-05-01 H
2
S Detector
Replacing Components of the H
2
S Detector
This section includes a procedure to replace the H
2
S sensor and the entire detector assembly.
In most cases, it is not necessary to replace the entire detector assembly.
Replacing the Plug-In H
2
S Sensor
CAUTION:
The sensor contains electrolyte which is a dilute acid. Do not disassemble the
sensor when replacing it with a new one. If sensor electrolyte comes in contact
with your skin, wash affected area thoroughly with soap and water.
1. Turn off the controller.
2. Turn off or unplug power to the controller.
3. Unscrew the detector housing cap from the detector housing body. Make sure not to lose
the cap gasket.
4. Unplug and remove the H
2
S sensor with the rubber boot and spacer attached.
5. Remove the rubber boot and spacer from the old sensor.
6. Remove the replacement sensor from its packaging and remove the wire jumper. This wire
jumper is installed on the sensor pins for shipment or storage but must be removed for the
sensor to operate properly when installed in a detector.
Slow or No
Response/
Difficult or
Unable to
Calibrate
• Unable to
accurately set the
zero or response
reading during
calibration.
• Detector requires
frequent calibration.
Note:
Under
“normal”
circumstances, the
detector requires
calibration once every
3 months.
Some applications
may require a more
frequent calibration
schedule.
• The calibration
cylinder is low, out-
dated, or defective.
• The flame arrestor in
the detector housing
cap is wet or clogged
with dirt or other
particulates.
• The calibration gas is
not an appropriate
concentration.
• The detector is
malfunctioning.
1. Verify that the calibration cylinder
contains an adequate supply of a
fresh test sample.
2. Check the detector housing cap to
determine if the flame arrestor is wet
or dirty. Clean if necessary.
3. Verify that the calibration gas
concentration is appropriate for the
detector. Zero emission air (20.9%
oxygen) is normally used for a zero
adjustment if the environment is
suspect and 25 ppm H
2
S in nitrogen
is normally used for a span
adjustment.
4. If the calibration/response difficulties
continue, replace the plug-in sensor
as described later in this section.
5. If the calibration/response difficulties
continue, contact RKI for further
instruction.
Condition
Symptom(s)
Probable Causes
Recommended Action
