12 • 65-2397RK CO
2
Transmitter
Start Up
This section describes procedures to start up the CO
2
transmitter and place the transmitter into normal
operation.
Introducing Incoming Power
1. Complete the installation procedures described earlier in this manual.
2. Verify that the power wiring to the controller is correct and secure. Refer to the controller
operator’s manual.
3. Turn on power to the controller.
4. Turn on the controller.
5. Verify that the controller is on and operating properly. Refer to the controller operator’s manual.
NOTE:
When first powered up, the transmitter will enter about a one minute period when the 4-20
mA output is stabilizing and may be above the controller alarm points or well below zero
momentarily. RKI controllers have a one minute warmup period when the controller does not
display any gas reading or give any alarm indication. The CO
2
transmitter’s 4-20 mA signal
should be stable by the time the controller’s warmup period is over.
CAUTION:
Allow the detector to warm up for 5 minutes before you continue with the next section,
“Setting the Zero Signal”.
Setting the Zero Signal
Since there is a background of CO
2
in air of typically 300 - 600 ppm (0.03 - 0.06% volume), it is
necessary to use a calibration kit with a 100% nitrogen cylinder to set the zero signal of a CO
2
transmitter with a low range detector. Fresh air can be used to zero the transmitter if a 0-20% volume,
0-50% volume, or 0-100% volume detector is being used.
WARNING: Do not remove the junction box cover while the circuits are energized unless the area
is determined to be non-hazardous. Keep the junction box cover tightly closed during
operation.
The procedure below describes applying 100% nitrogen 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.
1. Unscrew and remove the junction box cover from the junction box.
2. Set a voltmeter to measure in the millivolt (mV) range.
3. Plug the voltmeter leads into the test points on the amplifier. Plug the positive lead into the red (+)
test point; plug the negative lead into the black (
-
) test point.
4. Screw the calibration cup onto the bottom of the IR CO
2
detector.
5. Screw the regulator into the 100% nitrogen calibration cylinder.
6. Use the calibration kit sample tubing to connect the regulator to the calibration cup.
