Agilent Technologies 6850 Series Service Information page 282

6. Set the inlet pressure to 25 psi. The inlet
pressure should increase rapidly past the
25 psi setpoint and approach the line supply
pressure. You will feel pressure against the
septum (in this example 100 psi). The pneu-
matic configuration now matches the follow-
ing schematic:
Carrier supply
total flow in
100 psi
input pressure
Proportional
valve 1
If the pressure is still low, the problem is isolated
to:
• Insufficient supply pressure/flow volume to
the inlet EPC module
Released: April 2004
Flow sensor
mL/min
Total flow
control loop
• Leak at the gang fitting of the EPC module
• Cracked stainless steel tube on the insert
• Septum may have a hole in it
6850 Series Gas Chromatograph Service Procedures
Septum purge
regulator
Pressure sensor fixed @ 3 mL/min
psi
weldment
283