Installation and Start Up
| 3-19
Purging the Electronic Enclosure
A purge controller and vent system maintain a positive pressure prevent-
ing explosive gases from entering the electronics enclosure. On start-up,
the purge controller will automatically monitor the purge gas flow to
ensure a minimum of five (5) air exchanges before providing power to
the electronics enclosure . The controller then monitors the enclosure’s
internal pressure. In the event that positive pressure is lost, power will be
disconnected from the electronics. All input and output signals are discon-
nected by relays in the flameproof enclosure should power be interrupted
by the purge controller.
A regulated supply of instrument air or nitrogen must be connected
to the purge gas regulator. The regulator is located to the right of the
electronics enclosure. Refer to Chapter 2 for specifications.
The installer must install a second pressure regulator on the input
of the unit to mitigate any risk from a single regulator failure in the
system.
Once the analyzer is installed on a process gas pipe, instrument air
pressure must be maintained at all times, even when the analyzer is
powered down or off-line, to keep corrosive gases and moisture out of
the enclosures and prevent damage.
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CAUTION
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CAUTION
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CAUTION
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