Troubleshooting
6850
6850
Released: April 2004 6850 Series Gas Chromatograph Service Procedures 307
The recommended gas flows for the 6850 FID
are:
Carrier, packed columns: 30 to 60 mL/min
Carrier + Makeup, capillary columns:
30 mL/min
H
2
: set equal to or > the total carrier/makeup
flow
Air: 400 mL/min
Measure the flow rates for each gas indepen-
dently:
a. Cool the GC oven and turn off the inlet
pressure/flow to stop the column flow. If
there is any doubt as to column leaks, or
you are using a wide bore column,
disconnect the column and cap the FID
column fitting.
b. Turn on H
2
only and measure the actual
flow rate. It should be within 10% of
setpoint.
c. Turn off H
2
, turn on the Makeup gas and
measure the actual flow rate.
d. Turn on the H
2
flow and measure the
two gases together. The resulting actual
flow should be exactly the sum of the
two previous measurements. If it is
lower this could indicate a leak in the
column fitting at the detector base or a
partially plugged jet.
e. Turn off H
2
and Makeup gas flows. Turn
on the Air flow and measure the actual
flow rate.
Table 1-1 lists reasons and solutions for low FID
flow rates.
To Next Page
Loading...
Need help?
General
