RKI Instruments 35-3001-06-01 - Manual (Page 21)

35-3001-06-01 Combustible Gas/Oxygen Sample-Draw Detector • 17
Calibration, IR LEL Sensor
This section describes how to calibrate the IR combustible gas sensor of the sample-draw detector.
It includes procedures to prepare for calibration, set the zero reading, set the response reading, and
return to normal operation.
The standard calibration gas for the combustible gas sensor is methane. The sample-draw detector
may be calibrated to other combustible gases such as hexane or hydrogen. Use the correct
calibration gas for your installation.
NOTE: This procedure describes calibration using a demand flow regulator.
Preparing for Calibration
1. Follow the instructions in the controller’s operator’s manual for entering calibration mode.
NOTE: If you can verify a fresh air environment, it is not necessary to use the zero air calibration
cylinder to set the zero reading.
2. Screw the regulator into a zero air calibration cylinder.
Setting the Zero Reading
1. Connect the sample tubing from the demand flow regulator to the sample-draw detector’s inlet
line. This step is not necessary if you verified a fresh air environment earlier in this
procedure.
2. Allow the sample-draw detector to draw sample for one minute.
3. Follow the directions in the controller’s operator’s manual for setting the zero reading. If you
used a zero air calibration cylinder to set the zero reading, proceed to step 4. If you verified a
fresh air environment, proceed to the next section, Setting the Response Reading.
4. Disconnect the sample tubing from the inlet line.
5. Unscrew the regulator from the zero air calibration cylinder.
Setting the Response Reading
1. Screw the regulator into the combustible gas calibration cylinder.
2. Connect the sample tubing from the demand flow regulator to the sample-draw detector’s inlet
line.
3. Allow the sample-draw detector to draw sample for one minute.
4. Follow the directions in the controller’s operator’s manual for setting the span.
5. Disconnect the sample tubing from the inlet line.
6. Unscrew the regulator from the combustible gas calibration cylinder.
Returning to Normal Operation
1. Wait approximately one minute to allow the combustible gas reading to stabilize.
2. Follow the instructions in the controller’s operator’s manual to exit the calibration mode.
3. Store the components of the calibration kit in a safe and convenient place.