Chromatography Forum

Hello, Does anyone have experience in diagnosing a fault 68 Pump Stall on a Varian 9010 or 9012 pump? The operators manual suggests to check hydraulics for clogged line. I am getting mobile phase flow through the column. The motor/piston make three turns and then stops with this fault. I cannot see anything hindering the movement of the motor and piston. I swapped out the optical sensor with a working unit and this did not help. The pressure goes no higher than 20 barr. Thanks!

Hi,
Do you check plunger seal ? (or try to change new one plunger seal first)
Sometime system fault if system pressure do not meet requirement,

Make sure that upper pressure limit of the pump adjusted more than 20 bar !