Agilent Technologies 7890A Troubleshooting Manual page 76

5
Shutdown Symptoms
Column Shutdowns
76
The GC monitors inlet and auxiliary gas streams. If a carrier
gas (which can include an auxiliary flow module or
pneumatics control module) is unable to reach its flow or
pressure setpoint, the GC assumes that a leak exists. It will
warn you with a beep after 25 seconds, and it will continue
to beep in intervals. After about 5 minutes, the GC will shut
down components to create a safe state. The GC:
• Displays Front inlet pressure shutdown.
• Turns off to avoid column damage.
• Opens oven flaps in the back of the oven halfway.
• Flashes oven temperature setpoint Off.
• Turns off all flows for the column. When viewed, their
parameters flash Off. For example, the septum purge and
column flows for a split/splitless inlet would turn off.
• Turns off all other heaters. When viewed, their
temperature parameters flash Off.
• Attempts to turn on a shut- down zone fail with an error
message.
To recover from this state.
Fix the cause of the shutdown.
1
• Check for a broken column near the inlet.
• Check for leaks.
• Replace the inlet septum.
• Replace the inlet O- ring.
• Check the supply pressure.
2 Press the key for the device that initiated the shutdown.
Scroll to the pneumatic parameter that is flashing Off,
then press [On] or [Off].
For example, if the front inlet ran out of carrier gas,
press [Front Inlet], scroll to the pressure or flow parameter,
then press [On].
Troubleshooting