8 • 65-2405RK-05-04 Combustible Gas Transmitter
CAUTION:
The amplifier includes two additional potentiometers. They are factory-set. Do not adjust
them.
Test Points
The test points are on the left side of the amplifier (see Figure 2). The test points produce a 100 mV to
500 mV output that corresponds to the transmitter’s 4 to 20 mA output. Use the test points and a
voltmeter to measure the amplifier’s output during the start-up and calibration procedures. The black
test point in the lower left corner is the negative (-) test point and the red test point below the zero pot
is the positive (+) test point.
Amplifier Junction Box
The amplifier junction box protects the amplifier and wiring connections made to the amplifier. Use
the top 3/4 NPT conduit hub to connect wiring from the amplifier to the controller. Use the bottom
3/4 NPT conduit hub to wire the remotely installed combustible gas detector. Use the cover on the
front of the junction box to access the interior of the junction box. The amplifier is factory installed in
the junction box. Three spacers installed on the back of the junction box controls the distance of the
junction box from a mounting surface.
Detector Junction Box
The detector junction box is intended to be installed remotely from the amplifier junction box. The
combustible gas detector is factory installed in the bottom 3/4 NPT conduit hub. A terminal strip is
provided for wiring connections and the detector is factory wired to one side of this terminal strip. The
other side of the terminal strip is for user-supplied wiring to the detector terminal strip located in the
amplifier junction box. This wiring should go through the top 3/4 NPT conduit hub. Three spacers
installed on the back of the junction box controls the distance of the junction box from a mounting
surface.
Installation
This section describes procedures to mount the combustible gas transmitter in the monitoring
environment and wire the transmitter to a controller.
Mounting the Combustible Gas Transmitter
1. Select a mounting site that is representative of the monitoring environment. Consider the
following when you select the mounting site.
•
For the amplifier junction box, select a site where the junction box is not likely to be bumped
or disturbed. Make sure there is sufficient room to perform start-up, maintenance, and
calibration procedures. The site should be easily accessible.
•
For the detector junction box, select a site where the target gas is likely to be found first. For
lighter gases, mount the detector near the ceiling; for heavier gases, mount the detector near
the floor.
•
The junction boxes should be mounted no further than 200 feet from each other.
