18 • 65-2435RK CO Transmitter
Resetting the Zero Reading
The adjustment of the null potentiometer may result in a change in the zero reading, so the
zero reading may need to be adjusted.
NOTE:
If you can verify that the CO transmitter is in a fresh air environment, you do not need
to apply zero air to the detector before adjusting the zero reading.
1. Screw the regulator into the zero air calibration cylinder. Gas will automatically begin to
flow.
2. Allow the gas to flow for two minutes, then verify a reading of 100 mV (± 2mV). If
necessary, use the zero potentiometer on the amplifier to adjust the reading to 100 mV (±
2mV).
3. Unscrew the regulator from the zero air calibration cylinder.
Returning to Normal Operation
1. Remove the voltmeter leads from the amplifier test points.
2. Unscrew the calibration cup from the detector.
NOTE:
For convenience, leave the components of the calibration kit connected by the sample
tubing.
3. Secure the junction box cover to the junction box.
4. Return the controller to normal operation.
5. Verify that the controller display reading stabilizes at 0 ppm.
6. Store the components of the calibration kit in a safe and convenient place.
Calibration
This section describes how to calibrate the CO transmitter. It includes procedures to prepare
for calibration, set the zero reading, set the response reading, and return to normal operation.
It describes calibration using a fixed flow regulator which has no on/off knob and allows
sample to flow as soon as it is screwed into a cylinder. RKI Instruments, Inc. recommends
using a 0.5 LPM (liters per minute) fixed flow regulator.
CAUTION:
Do not adjust the null potentiometer during calibration. This will cause the
hydrogen compensation in the transmitter to operate improperly.
Preparing for Calibration
1. Screw the calibration cup onto the bottom of the CO detector.
2. Use the sample tubing to connect the fixed flow regulator to the calibration cup.
