PureAire Monitoring Systems, Inc.
10/25/07
9
3: Installation
3.1 Mounting
The
Air Check
✓
EX
monitoring system is packaged in an explosion-proof
housing with three ¾ inch NPT conduit hubs.
The system should be mounted on a vibration-free surface and out of direct
sunlight. The sensor should facing toward the ground.
3.2 Electrical
The
Air Check
✓
EX
is a 3-wire device. There is a positive 24 VDC power wire
and a positive output signal wire, which is typically 4-20 mA. The third wire is
system common and serves as power supply and signal returns. These connect to
the three point terminal block labels TB2. An earth ground lug inside the
enclosure is provided for earth grounding of shied wires.
PureAire recommends the use of a General Cable #E2203S.30.86 or equivalent
for analog output and 24 VDC power input. The maximum permissible cable
length is 0.62 miles (1 km).
PC Board for LEL catalytic sensors
TB1
LEL catalytic
sensor cell
Compensator,
Common and
Detector
Connections
c
o
n
n
e
c
t
i
o
n
s
TB2
Power,
Signal Out, and
Ground
Connections
