RKI Instruments RI-215A - Manual (Page 15)

RI-215A Operator’s Manual Start Up • 15
Preparing to Set the Zero
Connect the sample tubing from your calibration kit to the hose barb on the fixed flow
regulator. The fixed flow regulator should be a 0.5 LPM regulator.
NOTE: Do not connect the regulator to the calibration cylinder at this time.
Setting the Zero Reading
1. Locate the function switches on the bottom of the unit.
2. Press and hold the MODE switch (M) for three seconds to enter Maintenance Mode.
The display will show “1” to indicate Zero Adjustment Mode.
3. Press the SET switch (S) to enter Zero Adjustment Mode. The display will show a
reading with a flashing decimal point before the first and third digits, for example
“. 1.5“.
4. Remove the rubber cap covering the calibration gas inlet port at the bottom of the
unit.
5. Insert the calibration tubing into the gas inlet opening at the bottom of the RI-215A
and push the tubing over the calibration fitting.
6. Screw a 100% nitrogen calibration cylinder (a CO
2
-free source) into the regulator.
7. Allow the gas to flow for one minute or until the gas reading stabilizes.
8. Press the SET switch (S) and the unit will adjust the reading to zero. Be careful not to
breath onto the RI-215A since the CO
2
in your breath may affect the reading.
9. Press the SET switch (S) and the display will again show a “1”.
10. Unscrew the regulator from the nitrogen cylinder.
11. To return to normal operation, press the MODE switch for three seconds to exit
Maintenance Mode.