RKI Instruments 65-2498RK - Manual (Page 16)

12 • 65-2495RK/65-2498RK H
2
S Detector
Calibration
This section describes how to calibrate the H
2
S detector. It includes procedures to prepare
for calibration, set the fresh air reading, set the response reading, and return to normal
operation. It describes calibration using a calibration kit that includes a calibration cup,
calibration gas, sample tubing, and a fixed flow regulator with an on/off knob. RKI
Instruments, Inc. recommends using a 0.5 LPM (liters per minute) fixed flow regulator.
WARNING: Not using the recommended calibration cup and sample flowrate will
result in an inaccurate calibration. See“Parts List” on page 13 for the
required calibration cup and regulator.
Preparing for Calibration
1. Screw the calibration cup onto the bottom of the H
2
S detector.
2. Screw the regulator into the zero air calibration cylinder. Make sure the regulator is
off. It is off when the on/off knob is turned all the way clockwise.
3. Use the sample tubing to connect the regulator to the calibration cup.
NOTE If you can verify that the H
2
S detector is in a fresh air environment, you do not
need to apply zero air to the detector before adjusting the fresh air reading.
4. Put the controller into its calibration program. See the controller operator’s manual
for instructions to enter the calibration program.
Setting the Zero (Fresh Air) Reading
1. Follow the instructions in the controller operator’s manual for setting the zero
reading.
2. When the instructions call for applying zero air to the detector, turn the regulator’s
on/off knob counterclockwise to open it. Gas will begin to flow.
3. Allow the gas to flow for two minutes.
4. Set the fresh air reading according to the controller operator’s manual.
5. Turn the regulator’s on/off knob clockwise to close it.
6. Unscrew the regulator from the zero air calibration cylinder. Leave the sample tubing
connected to the regulator and the calibration cup.
NOTE: Depending on the size of your zero air cylinder, it is possible that you will have a
different regulator for the zero air cylinder and the H
2
S gas cylinder. If necessary
to fit the H
2
S calibration gas cylinder, change the regulator.
Setting the Response Reading (Span)
1. Screw the regulator into the calibration gas cylinder. Make sure the regulator is off. It
is off when the on/off knob is turned all the way clockwise.
2. Follow the directions in the controller operator’s manual for setting the response
(span) reading.
3. When the directions call for exposing the detector to gas, turn the regulator’s on/off