RKI Instruments 65-2498RK - Manual (Page 6)

65-2495RK/65-2498RK H
2
S Detector • 6
Detector Housing Body
The detector housing body protects the electronic components within the housing. Use the
mounting threads at the top of the housing to screw the H
2
S detector into a 3/4” NPT hub.
Two wires extend from the top of the detector housing body. Use these wires to connect
the detector to a controller. One of the wires is black and one of the wires is red.
The housing body includes a four-socket pattern at the bottom of the housing body. The
plug-in sensor mates to this socket pattern. A pre-amplifier located between the sockets
and the two wires conditions the sensor’s signal before the signal reaches the controller.
Housing Cap & Cap Gasket
The housing cap screws onto the detector housing. It retains the sensor and protects it
from damage. A foam gasket inside the housing cap seals against the face of the sensor
when the cap is screwed on the housing body. A hydrophobic membrane on the outside of
the cap face keeps water and particulates away from the sensor face behind the cap.
Unscrew the detector cap to access the sensor for replacement. A cap gasket seals the
interface between the housing and cap.
Plug-in Sensor
The plug-in sensor is secured in the detector assembly by the housing cap. Through a
series of chemical and electrical reactions, the sensor produces an electrical output that
corresponds to the detection range of the detector.
Junction Box
The junction box allows you to install the H
2
S detector at a mounting site that is remote
from a controller and protects the detector wiring connections. Two conduit hubs allow
you to mount the detector to the junction box and connect the wiring from the detector to
a controller. Three spacers installed on the back of the junction box control the distance of
the junction box from a mounting surface and insure that there is enough room to install a
calibration cup on the detector during calibration. A terminal block within the junction
box facilitates the wiring connections. A cover on the front of the junction box allows
access to the interior of the junction box.
Installation
This section describes procedures to mount the H
2
S detector in the monitoring
environment and wire the detector to a controller.
Mounting the H
2
S Detector
NOTE: If you are installing a 65-2495RK, it does not include a junction box and is usually
factory installed in one of a controller’s conduit hubs or may be field installed
using the 3/4” NPT threads on the end with the wires. The 65-2498RK includes a
junction box as shown in Figure 3 below.
1. Select a mounting site that is representative of the monitoring environment. Consider
the following when you select the mounting site.
• Select a site where the detector is not likely to be bumped or disturbed. Make sure
there is sufficient room to perform start-up, maintenance, and calibration
procedures.
• Select a site where the target gas is likely to be found first.