Maintenance • 23
CAUTION:
Allow the replacement sensor to warm up for 5 minutes before you continue.
11. Calibrate the replacement sensor as described in “Calibration, LEL Sensor” on page 28.
Replacing the LEL Amplifier
1. Turn off the controller.
2. Turn off power to the controller.
3. Open the housing door of the sample-draw detector.
4. Remove the detector and controller plug-in terminal strips by grasping the sides of the
strips with your fingers. Let the terminal strips hang by their connected wires while you
replace the amplifier.
5. Unscrew the screw in the lower left corner of the amplifier and remove the screw, lock
washer, and flat washer. Be careful not to lose any of these parts.
6. Remove the old amplifier from the main circuit board.
7. Install the new amplifier in the same orientation as the old amplifier. See Figure 1.
8. Reinstall the screw, lock washer, and flat washer you removed in step 5.
9. Install the detector and controller plug-in terminals strips into their sockets on the new
amplifier. If controller leads or detector cable leads were removed from the plug-in
terminal strips during this procedure, refer to Table 2 and Table 3 below.
Table 2: Reconnecting the Amplifier
to the Detector/Amp Terminal Strip
Amplifier Controller
Terminal Strip
Detector/Amp Terminal
Strip on Main PCB
PWR/SIG “-”
-
PWR/SIG “S”
S
PWR/SIG “+”
+
Table 3: Reconnecting the LEL Sensor to the Amplifier
Amplifier Detector
Terminal Strip
Detector Lead
DETECTOR “R”
RED
DETECTOR “W”
WHT
DETECTOR “G”
GREEN
DETECTOR “B”
BLK