35-3010A-09 Sample-Draw Detector • 3
bottom of the housing to make wiring connections.
An aluminum subpanel is mounted to the interior of the housing. The sample-draw
detector’s internal components are mounted to the subpanel.
Flow System
The sample-draw detector’s flow system consists of the INLET fitting, hydrophobic filter,
charcoal filter, pump, flowmeter, bypass valve, status lights, pressure switch, flow blocks,
and EXHAUST fitting (see Figure 1). Figure 2 illustrates how the gas sample moves
through the flow system.
Figure 2: Sample Draw Detector Flow Diagram
INLET Fitting
The INLET fitting on the bottom of the housing allows the gas sample to enter the sample-
draw detector. The INLET fitting accepts 1/4 in. rigid tubing. See “Installation” on
page 10 for instructions to connect tubing to the INLET fitting.
Hydrophobic Filter
The hydrophobic filter is to the left of the main circuit board. It is held in place by a metal
clip. It prevents water and other liquids from contaminating the flow system. Replace the
filter when it appears dirty, discolored, or clogged. If a liquid other than water is drawn
into the filter, replace the filter as soon as possible.
Charcoal
Filter
CO
Dum my
Plug
Pressure Switch
H2S
Dum my
Plug
IR CH4
Oxygen
Flow meter
Bypass
Valve
Flow Block
LEL
Dum my
Plug
Pump
Exhaust
Inlet
Hydrophobic
Filter
