RKI Instruments 35-3010RK-06-02 - Manual (Page 9)

35-3010RK-06-02 Sample-Draw Detector • 5
Flow Blocks
Both flow blocks are located in the lower right corner of the sample-draw detector. The
oxygen and CO sensors are installed in the larger flow block. The smaller flow block
houses the IR CO
2
sensor. The flow blocks route the sampled air to each sensor.
EXHAUST Fitting
The EXHAUST fitting on the bottom of the housing allows the gas sample to exit the
sample-draw detector. The EXHAUST fitting accepts 1/4 in. rigid tubing. See
“Installation” on page 8 to connect tubing to the EXHAUST fitting.
Detection System
The detection system consists of the gas sensors, preamp circuit board, and the main
circuit board.
Combustible Gas Sensor
The combustible gas sensor is normally installed in the lower left of the larger flow block.
In this model, the combustible sensor has been replaced by a dummy plug.
Oxygen Sensor
The oxygen sensor is installed in the lower right of the larger flow block. It consists of a
cylindrical body which houses the detection elements and a cable which terminates in a
round 7-pin male connector. The sensor connector mates to a 7-position socket that is
wired to the main PCB.
Hydrogen Sulfide Gas Sensor
The hydrogen sulfide sensor is normally installed in the upper right of the larger flow
block. In this model, the sensor has been replaced by a dummy plug.
Carbon Monoxide Sensor
The carbon monoxide gas sensor is installed in the upper left side of the flow block. It has
4 pins which mate with sockets in the preamp circuit board.
Carbon Dioxide Sensor
The infrared carbon dioxide sensor is installed in the smaller flow block. A small circuit
board with a cable mates to it and retains it in the block. The cable is wired to the main
PCB.
Preamp Circuit Board
The preamp circuit is used to connect the CO sensor to the main circuit board and to
secure the sensor in the flow block. Two cables mate to the main circuit board: the one on
the left is for the CO sensor signal and the one of the right is for the H
2
S sensor signal.
Since there is no H
2
S channel, the cable on the right is not used.