Low pressure+1100 LC+six port valve of triple quad

[sartaj]

There is a drop in cap pressure after valve switch from detector to load; the starting pressure is 60 bar but after valve switch it stablizes at 10-12 bar. What are the possible causes? I have made sure there are no leaks!

[richiekichi]

Is this an Agilent triple quad? The rotor seal and/or stator face in the MS switching valve may need replacing or there could be a blockage in the waste line. You can remove the switching valve and try giving all the bits in there a clean to get a bit more life out of it.