Agilent Technologies 5975T LTM GC/MSD, Troubleshooting And Maintenance Manual

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184 Troubleshooting and Maintenance Guide
12
Vacuum System
Common Vacuum System Problems
Air leak symptoms
The most common problems associated with any vacuum
system are air leaks. Symptoms of air leaks include:
• Loud gurgling noise from the foreline pump (very large
leak.)
• Inability of the turbo pump to reach 95% speed
• Higher than normal high vacuum gauge controller readings
The 5975T LTM GC/MSD will not pump down successfully
unless you press on the side plate (analyzer door) when you
turn on the instrument power. Continue to press until the sound
from the foreline pump becomes quieter.
Pumpdown failure shutdown
The system will shut down both the high vacuum and the
foreline pump if the turbo pump speed is below 80% after
7 minutes.
This is usually because of a large air leak: either the side plate
has not sealed correctly or the vent valve is still open. This
feature helps prevent the foreline pump from sucking air
through the system, which can damage the analyzer and pump.
To restart the instrument, find and correct the air leak, then
switch the power off and on. Be sure to press on the side plate
when turning on the instrument power to ensure a good seal.