On a Infinity 1290
A) 50% H2O / 30% acetonitrile / 20% isopropanol (v/v/v) containing 10mM ammonium formate
B) 1% H2O / 9% acetonitrile / 90% isopropanol (v/v/v) containing 10mM ammonium formate.
Pump A has been giving pressure problems for the last 2 days but got working after purging, priming, conditioning, and letting it flow for some time.
Today, there is no pressure in pump A. When Pump B is at 100%, all look good. Normal-pressure. As soon as we start giving some %A, the pressure falls. At 100% A, there is no pressure.
Also, we noticed that purging A, you can see the tubing from the bottle going forward and backward.
I guess some valves need to be cleaned or changed in pump A. What do you suggest?