No pressure in a Varian GC/MS 4000

[jahi]

Hi. I'm working with an old Varian GC/MS 4000. Since some days it couldn't get ready for analyze samples cause the pressure did't rise. The GC remained, usually, around 2 psi instead of 30 psi. the problem have been solved with a fan in front of the gc without a pannel (directed in the electronic flow system). With the air movment it got the right pression (this as happened for some weeks). During an analysis it stopped working. we tried to bypass the injector, to calibrate the flow and check for lick but the pressure now are set on value zero.
If someone can help us it would be amaizing

[Jihad]

Hi,
You need to check,
injector nut tightened well enough.
Capillary column nut is tight enough.
Column has not got any breakage.
Make sure no leakage in the efc or in the tubing joints.
Septum purge calibration.

Regards,
Jihad
Kuwait

[Peter Apps]

Hi. I'm working with an old Varian GC/MS 4000. Since some days it couldn't get ready for analyze samples cause the pressure did't rise. The GC remained, usually, around 2 psi instead of 30 psi. the problem have been solved with a fan in front of the gc without a pannel (directed in the electronic flow system). With the air movment it got the right pression (this as happened for some weeks). During an analysis it stopped working. we tried to bypass the injector, to calibrate the flow and check for lick but the pressure now are set on value zero.
If someone can help us it would be amaizing

It sounds very much as if the EFC electronics were overheating, and are now completely dead. You probably need to replace the electronics module. As a double check. Remove the column from the detector and dip the end into some clean solvent - if you see bubbles you have flow, which means that the EFC is reading wrong. Check also for flow at the split and septum purge outlets.

Peter