35-3010A-12 Sample-Draw Detector • 19
Recommended Action
1.
Verify that the calibration cylinder contains an adequate supply of a fresh test sample.
2.
If necessary, set the correct flow rate with the bypass valve or flow adjust potentiometer.
3.
If you cannot set the correct flow rate, check the sample line for obstructions or kinks.
4.
If the calibration/response difficulties continue, replace the sensor as described later in this
section.
5.
If the calibration/response difficulties continue, contact RKI Instruments, Inc. for further
instruction.
Replacing Components of the Sample-Draw Detector
This section includes procedures to replace the sensors, the hydrophobic filter, and the charcoal
filter.
Replacing the Oxygen Sensor
1.
Turn off incoming power.
2.
Open the housing door of the sample-draw detector.
3.
Unscrew and remove the two screws that secure the retaining plate, then lift the plate,
connector, and sensor out of the housing.
4.
Unplug the connector from the socket that leads from the sensor.
5.
Plug the socket of the replacement sensor into the connector.
6.
Place the sensor in the oxygen sensor cavity, then position the retaining plate on the two
standoffs.
7.
Secure the retaining plate to the standoffs with the two screws you removed in step 3.
8.
Turn on incoming power.
9.
Calibrate the replacement sensor as described in “Calibration, Oxygen Detector” on page 22.
Replacing the Carbon Monoxide Sensor
1.
Turn off incoming power.
2.
Open the housing door of the sample-draw detector.
3.
Unscrew the 5 screws that retain the preamp circuit board.
4.
Lift the preamp circuit board away from the flow block.
Be careful not to pull on the cables that connect the preamp circuit to the main
circuit board.
There is a foam gasket in the bottom of each flow cavity beneath the circuit board.
Make sure the gaskets stay in place.
5.
Pull the CO sensor off the preamp circuit board. It is located in the amp 1 position (left side) of
the preamp circuit board.