RKI Instruments 35-3001-01 - Manual (Page 7)

35-3001-01 Combustible Gas Sample-Draw Detector • 3
installation where general purpose equipment is in use.
The housing door is hinged on the left side and is secured by two latches on the right side. The
flowmeter and status LEDs are visible through a window in the housing door.
Four mounting feet are attached to the back of the housing (one at each corner). Use the mounting
feet to install the housing to a vertical surface.
Sample Fittings
The sample fittings are located on the left side of the bottom of the housing. The inlet fitting is near
the front of the housing and the exhaust fitting is near the back of the housing. The inlet fitting has
a short factory installed tubing stub for use with the particle filter. The sample fittings accept 1/4 in.
rigid tubing. See the Installation section on page 6 to connect tubing to the sample fittings.
Inlet Fitting Tubing Stub
A short tubing stub comes factory installed in the inlet fitting. It is used for connecting the particle
filter. If the particle filter is not used, or if you install the particle filter in a different location, the
tubing stub needs to be removed and replaced with tubing.
Conduit Hub
One 3/4” conduit hub is located on the right side of the bottom of the housing. It is used for routing
wiring into the housing by using conduit or an appropriate cable bushing.
Internal Components
This section describes the sample-draw detector’s internal components (see Figure 1). Figure 2
illustrates how the gas sample moves through the flow system.
Figure 2: Combustible Gas Sample-Draw Detector Flow Diagram
Main Circuit Board
The main circuit board includes the detector/amp terminal strip, interconnect terminal strip, oxygen
sensor terminal strip, pump connector, and flowmeter circuit board connector (see Figure 1).
Pump
Flowmeter
LEL
Sensor
Particle Filter
Flowmeter PCB
Exhaust
Pressure Switch
Hydrophobic Filter
Inlet
Restrictor
Sensor
Flow
Control
Valve