Agilent Technologies 6890 Series Service Manual page 547

840 Shutdowns
Shutdown 2—Oven cryo shutdown
Shutdown 2—Oven cryo shutdown
Cryogenic shutdowns prevent liquid coolant from being wasted when the GC
is unable to start a run. A cryo shutdown does not indicate that the cryogenic
cooling system is malfunctioning. Instead, one of the following could be the
cause:
A "cryo timeout" has occurred.
A timeout occurs if the GC oven has reached its temperature setpoint but
the amount of time you specified for the cryo timeout setpoint has elapsed
without a run beginning.
Turn the oven off and then on again or change the setpoint to restore
normal operation. Then, turn the timeout option off to prevent the shutoff
from reoccurring, or lengthen the timeout period.
A "cryo fault" has occurred.
Cryogenic cooling has been on for over 16 minutes, but the oven has not
reached its temperature setpoint.
Check the level of the cryogenic fluid, and replace the supply if it is too
low for proper cooling.
The cryo valve may be stuck open or closed. If your fluid supply is
adequate, the valve may be broken or the electronics driving it may be
malfunctioning (this is a less likely cause).
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Error Codes and Internal Diagnostics
Agilent 6890 Gas Chromatograph Service Manual
Jun 2001