pump head broken (hopefully not)

[cottrel]

Hi all,

the system we have in our lab is a Gilson with a 322 pump.

The ACN pump is not pumping, or at least it is but really slowly and definitely not at 1ml/min.

The software controlling the machine (Trilution) tells you when one pump is not working (drops in gradient line) but it is not doing that now. Also the fact that it still detects 1mL/min flow rate on just 100% ACN means that the pump is working (right?) but I can tell that no or little solvent is passing through. It's not a blockage (the pressure stays really low 4bar compared to ca 70 bar as it used to normally).

I checked the tubings between the ACN bottle and the pump head, but I couldn't manage to make the pump head suck any solvent but still it is doing the typical sound. I still have the feeling that the problem is in the tubing but I couldn't find a definitive test for that.

Any suggestion would be much appreciated,

Many thanks,

Manuel

[bisnettrj2]

Sounds like a leak in the pump seal or a bad check valve to me. I'm not familiar with that particular instrument, but if the mobile phase is gravity fed (e.g. - the mobile phase bottle is above the pump), then you should be able to undo the mobile phase line at the pump from the bottle and you should get flow - at about 5-10 mL/minute. If the line is under pressure (nitrogen-pressurized vessel or similar), you should be able to do the same thing, but maybe not with the same resulting flow rate. If you get no flow, you may have a blocked filter/frit in the mobile phase container. If you have good flow, you might have a bad pump seal, a non-functioning check valve, an air bubble stuck in the pump head. Heck, you could have a broken piston. You should have a look at the maintenance and troubleshooting section of the pump user's guide for a guideline on how to disassemble the pump head and for some tips on what may be causing your particular issue. Or, call Gilson.

http://www.gilson.com/resources/321322_ ... _guide.pdf

[SiPeel]

check the pump head setting on the pump, it could be set at the wrong volume which would cause the flow to be incorrect. the back up batteries on old gilson pumps can go so if you've switched it off recently it could have lost its settings

[Xchem]

Did you happen to solve the problem, I'm having a similar issue.