RKI Instruments 35-3000RK-LEL - Manual (Page 8)

8 • 35-3000RK-LEL Combustible Gas Sample-Draw Detector
Sensor leads
Four color-coded leads extend from the connector. The leads allow you to connect the
combustible gas sensor to the main circuit board.
Main Circuit Board
The main circuit board includes the interconnect terminal strip, detector terminal strip,
pump terminal strip, and relay (see Figure 1).
NOTE: The flowmeter and status lights are mounted to the main circuit board but are
considered part of the flow system.
Interconnect terminal strip
The interconnect terminal strip is the nine-point terminal strip near the bottom edge of the
main circuit board. Use the interconnect terminal strip to connect the sample-draw
detector to a controller
Detector terminal strip
The detector terminal strip is the nine-point terminal strip near the right edge of the circuit
board. Use the detector terminal strip to connect the combustible gas sensor to the main
circuit board.
NOTE: The combustible gas sensor is factory-wired to the circuit board. See the
“Installation” section on page 9 for all wiring procedures related to the sample-
draw detector.
Pump terminal strip
The pump terminal strip is the four-point terminal strip near the top edge of the circuit
board. Use the pump terminal strip to connect the pump and pressure switch to the main
circuit board.
NOTE: The pump and pressure switch are factory-wired to the circuit board. See the
“Installation” on page 9 for all wiring procedures related to the sample-draw
detector.
Relay
The relay is to the left of the detector terminal strip. The relay is single-pole, double-throw
(SPDT) and is rated for 2 amps at 25 VDC (resistive). If the pressure switch senses a low
flow condition, the relay interrupts the signal from the sensor. The interrupted sensor
signal causes a fail condition at the controller