Agilent Technologies 6890 Series Service Manual page 564

If the oven sensor is operating correctly and the error persists, the main
board must be replaced.
See Fault 221—Thermal shutdown (status message).
Fault 223—Oven thermal shutdown
Status message: Oven temp too cool
The oven temperature reading indicates the oven is less than its minimum
allowable temperature. This indicates a stuck open cryo valve or a shorted
oven sensor.
Power to the small zones is disabled. To clear the error message, turn off all
the heated zones and turn the GC off and then on again.
See Fault 221—Thermal shutdown (status message).
Fault 224—Oven thermal shutdown
Status message: Oven temp sensor
The oven temperature reading reports the oven's temperature is lower than
expected, which indicates a shorted oven sensor. Power will be turned off for
all the heated zones.
The sensor must be replaced.
See Fault 221—Thermal shutdown (status message).
Fault 225—Front detector thermal shutdown
Status message: F det temp too hot
The front detector's temperature is higher than the maximum allowable
temperature (detector type maximum temperature plus an additional 25° C).
This indicates a defective heater drive on the mainboard or a defective sensor.
Power is disabled to all the heated zones. This fault can only be cleared by
turning off all the heated zones and turning the instrument off and on again.
The problem could be caused by a defective sensor or defective heater
driver on the mainboard.
See Fault 221—Thermal shutdown (status message).
Jun 2001
Fault 223—Oven thermal shutdown
Error Codes and Internal Diagnostics
Agilent 6890 Gas Chromatograph Service Manual
Faults 850
9 of 22