Pressure maximum exceeded on RI detector - baseline unstable - flow cell possibly damaged?

We have a system with the following parts. 

  • Tray with THF Bottle as solvent A/no solvent B and Waters in Line Degasser
  • 1200 Series G1312A Binary Pump
  • 1100 Series G1313A Autosampler
  • 1100Series G1316A Column Compartment with guard column and analytical column in sequence
  • 1200 Series G1362A RI Detector

It has a baseline issue, was sitting for a long time unused and fixing and replacing the following things did not improve it:

  • Both solvent lines are drawing solvent from the same bottle
  • replaced solvent filters
  • hooked the system up properly (channel B was not hooked up at all and the capillaries were connected wrong)
  • changed the pump seals and did a pump-wear in procedure
  • cleaned the pistons and the inside of the pump
  • exchanged the active inlet valve and the outlet valve on both pump heads
  • exchanged the cartridge in the purge valve
  • primed degasser and pumps with IPA

I am currently bypassing columns for testing and the baseline shows a lot of noise. I am currently trying to clean the flow cell as I was told that this may be the issue. I would like to open the flow cell, but cannot find a description of how to do this in the manual. 

It says that the maximum pressure of 5 bar should not be exceeded for the flow cell, but since I did not know that when I initially tested the instrument, I exceeded that pressure for sure based on the pressure reading of the pump. What happens to the flow cell when it is overpressurized. If I am running the system at 1 mL/min (typical flow rate for previous samples), pressure is already at 6 bar. I thought I can go up to 5 mL/min and be fine, but maybe 5mL/min is just for purging. 

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