Primary pump issues
We are relatively new to UPLC, and are not sure how to even classify this problem. We had a full PM on our BSM in August 2012. Things were working well until Nov 2012, at which time we had erratic pressures and when running a static decay test primary pump B seemed to be the problem. We were told by a Waters tech to change the plunger and seals, which we did, and things went well for awhile. Last week we noticed that retention times were shifting quite a lot, and in running the static decay test/dynamic leak test we can't get primary pump A or B to pass. The message we get is unable to compress or unable to maintain pressure. We have tried changing seals again (which seems excessive...should we have to change seals every 2 months?) and this has not helped, same results/messages when running the static decay/dynamic leak test. We would appreciate any tips, suggestions, etc. as we are at a loss.