Purge Override Option - ABB PGC2000 Operation And Service Manual

The X Purge cycle time depends totally on the application, but it may vary with analyzer configuration
and condition. Refer to the analyzer label or Data Package for specific purge specifications. Once X
Purge applies power to the analyzer, power continues to the analyzer as long as the electronics
housing maintains air purge pressure.
X Purge removes power from the analyzer when the electronics housing air purge pressure drops
below specifications. It locks out power to the analyzer and causes a purge alarm contact to switch.
The analyzer has connections available to the customer for connecting the purge alarm to a visual or
audible annunciator located in a constantly monitored area.
In order to re-start the analyzer after an X Purge alarm, you must first correct the cause of the drop in
pressure. Then turn the power OFF at the circuit breaker for at least ten seconds and turn the power
back ON. This starts a new X Purge timed cycle, which it must complete before it will supply power to
the analyzer. If you do not correct the cause and cannot achieve and maintain pressure, the X Purge
will not complete the cycle and will not supply power to the analyzer.
When X Purge removes and locks out power to the analyzer after a drop in electronics housing purge
air pressure (or before pressure has initially attained the specified level), you can use Override to
provide power to the analyzer for troubleshooting or maintenance purposes. Override does not
cancel the X Purge power lockout but temporarily overrides it.
X Purge Override Option
Before you enable X Purge Override to override its control of power to the
analyzer, ensure the area where the analyzer is located is safe and hazard free, and
remains so for the entire time the X Purge housing cover is removed.
Override must not be left on during regular operation of the analyzer.
Use the X Purge Override Option only for start up, troubleshooting, and maintenance. Do not leave it
on during regular operation of the analyzer. Override requires a well-lighted area to function. A light
sensor inside the X Purge housing allows you to enable Override after you remove the X Purge
housing cover. When you replace the cover, the light sensor cancels Override.
The following steps describe how to use the override function.
1. Ensure the area is safe and well-lit.
2. Remove the X Purge housing cover and press the Override button (see Figure 4-36) to apply
power to the analyzer.
All versions of the X Purge have a set screw in the lid that must be removed before
the housing cover can be removed.
3. Perform the necessary maintenance and troubleshooting.
4. When you have completed the maintenance and troubleshooting, replace the X Purge housing
cover (and the set screw).
5. To cancel Override safely and properly and to reset X Purge, turn the supply power OFF at the
circuit breaker outside the analyzer (for at least ten seconds) and then turn power ON again.
2000-OSM, F1
WARNING
CAUTION
NOTE
4-36