Owner's manual
6 • 65-2405RK-03 Combustible Gas Transmitter
Wiring the Detector to the Amplifier
WARNING: Always verify that the power to the controller is off before you make 
wiring connections.
1. Confirm that no power is being applied to the amplifier. If the amplifier has already 
been connected to a controller, turn off the controller and turn off or unplug power to 
the controller.
2. Remove the detector junction box’s cover from the junction box.
3. Remove the amplifier junction box’s cover from the junction box.
4. Guide a four-conductor, shielded cable or four wires in conduit through the top 
conduit hub of the detector junction box. To make wiring more convenient, use wire 
colors that correspond to the detector wire colors: red, white, green, and black.
NOTE: Consult RKI Instruments, Inc. for cable lengths longer than 200 feet.
5. Connect the detector leads to the terminal block in the detector junction box.
6. Secure the detector junction box’s cover to the junction box.
7. Guide the other end of the four-conductor, shielded cable or four wires in conduit 
through the bottom conduit hub of the amplifier junction box.
8. To gain access to a plug-in terminal strip for wiring, pull it out of its socket by 
grasping the terminal strip and pulling. The detector strip is keyed so that the 
controller and detector terminal strips cannot be reversed inadvertently.
9. Pull out the detector terminal strip and connect the four wires to the terminal strip as 
follows (see Figure 3).
• Connect the wire corresponding to the detector’s red wire to the LEL “R” 
terminal.
• Connect the wire corresponding to the detector’s white wire to the LEL “W” 
terminal.
• Connect the wire corresponding to the detector’s green wire to the LEL “G” 
terminal.
• Connect the wire corresponding to the detector’s black wire to the LEL “B” 
terminal.
CAUTION: If shielded cable is used, leave the cable shield’s drain wire disconnected and 
insulated at the detector junction box. You will connect the opposite end of the cable’s 
drain wire to the amplifier junction box’s chassis (earth) ground.










