I use a Waters UPLC for routine analysis and I noticed when you load up the BSM you see a Performance icon where you get values for Pump A and Pump B C/D Ratio, I looked up the manual and it describes the value as the pressure ripple in the pump and should be ideally less than 2.
Does this mean if its over 2 that there is a blockage in the lines or a problem outside the lines like faulty check valve, pressure transducer etc? I cant find any more detailed info on this reading and what exactly it means.

Thanks for reading.