Operation
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GA01423_002_C0 - 10/2016 - © Leybold
4.4 Shutdown
After vapour has been pumped, continue to operate the pump with the purge
gas valve open for over one hour. If you close the purge gas valve port or
stop the pump soon after vapour has been pumped, condensed moisture
remains in the pump, resulting in failure.
■
To prevent the drawback of debris from the vacuum pump into vacuum
chamber during shutdown, close the isolation valve (open the purge gas
valve if one is installed).
■
Switch the vacuum pump off.
When the pump stops, atmospheric air is drawn back from the purge gas
valve port to the inside of pump, and pressure inside pump rises to about
atmospheric pressure. To maintain vacuum in the vacuum chamber and pre-
vent the drawback of debris from vacuum pump into vacuum chamber, close
the isolation valve to the vacuum chamber before shutting off the pump.
