RKI Instruments 35-3000RKA-10 - Manual (Page 24)

24 • 35-3000RK-10 PPM Hexane Sample Draw Detector
Preparing for Calibration
NOTE: Calibrating the sample draw detector may cause alarms. Be sure to put the
controller into calibration mode or disable external alarms before continuing.
1. Put the controller into calibration mode or disable external alarms.
2. Open the sample draw detector’s housing door.
3. Set a voltmeter to measure in the DC millivolt (mV) range.
4. Plug the positive lead into the red + test point; plug the negative lead into the black -
test point.
5. Use the following formula to determine the correct test points output for the
calibrating sample.
Output (mV) = (calibrating sample/fullscale) X 400 + 100
For example, with a calibrating sample of 250 ppm hexane and a fullscale setting of
500 ppm hexane, the correct output is 300 mV.
300 (mV) = (250/500) X 400 +100
Assembling the Calibration Kit
NOTE: If you can verify a fresh air environment, it is not necessary to use a zero air
calibrating sample to set the zero reading. Screw the dispensing valve onto the
hexane calibration cylinder and go to the next section, “Setting the Zero
Reading.”
1. Screw the dispensing valve onto the zero air calibration cylinder.
2. Run one end of the humidifier tube through the tubing clamp provided with the
calibration kit and connect this end to the fitting on the gas collection bag.
WARNING: The humidifier tube used with this calibration kit includes polyurethane
tubing on each end of the humidifier tube to facilitate making connections
to hose barbs. Do not clamp on the middle braided tube section of the
humidifier tube. Only clamp on the polyurethane tube on either end of the
braided humidifier tube.
NOTE: For best accuracy, RKI Instruments, Inc. recommends calibrating the sample
draw detector by introducing the calibration gas at the end of the inlet sample
line and not using a shorter temporary inlet line.
3. Connect the humidifier tube from the gas collection bag to the inlet sample line.
Allow the sample draw pump to draw out any residual gas in the gas collection bag.
4. Close the tubing clamp.
NOTE: This step will cause a low flow alarm.
5. Disconnect the humidifier tube from the inlet sample line.