Chapter 7 Troubleshooting
GC-2014 Service Manual
100
(3) The total flow rate is higher than the setting.
Check that I time = 1, P term = 15, and I term = 40.
If the values are different from the above values, input these values and
press the pf4 key to write them in the ROM.
Check the offset and gain values for the flow rate.
The offset value is normally in the range 32,000 to 33,500 and the gain
value is normally in the range 3,000 to 6,000. If the offset value is well
outside this range, perform offset calibration. (The method is described in
the GC-2014 instruction manual.) If the gain value is well outside this range,
obtain the correct value from Shimadzu Corporation's Quality Assurance
Department. At this time, provide notification of the serial number and lot
number displayed on the side of the AFC.
If the gas is still flowing into the carrier line even when the power is turned
OFF, replace the AFC.
(4) The inlet pressure fluctuates (unstable).
Check that I time = 1, P term = 100, and I term = 150.
If the values are different from the above values, input these values and
press the pf4 key to write them in the ROM.
If a glass insert for WBI is used, set the column insertion length (normally
34 mm) to approx. 15 mm.
Set the inlet pressure to 0 kPa and the total flow rate to 400 ml/min. At this
time, pressure is generated due to the flow-line resistance of the split line.
The specified value for this pressure is 50 kPa or less. (The effective value
is 30 kPa or less.) If it is greater than 50 kPa, identify the place where
resistance exists using the following procedure.
Remove the AFC's piping-line joint with the "s" mark band, one piece at a
time. If the pressure decreases when the joint on the lower stream of the
filter is removed, resistance exists in the split line inside the AFC. Next,
remove the joint on the upper stream of the filter. If the pressure decreases,
the filter is clogged. Prepare a new filter. Next, remove the joint on the upper
stream of the buffer. If the pressure decreases, the buffer is clogged. If the
pressure does not decrease, the cause originates in the INJ. Check the
glass insert and the split line inside the INJ.
Check that there is no clogging in the purge-line flow line.
The inlet pressure sensor in the AFC is inside the purge line. If there is
resistance in the purge line, the pressure may fluctuate.
(5) The inlet pressure is lower than the setting (in split mode).
Check for leaks using, for example, a snoop.
Check whether or not the total flow rate is controlled in accordance with the
setting. If it is not, perform the checks described previously in items (1) to
(3).
Check that the source pressure (i.e., the primary pressure) has attained a
sufficient level. The source pressure can be ascertained by viewing the
"Actual" value for the primary pressure in the Flow Adjust
window. It is not
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