- Pump overpressure
- Flow Through Needle (FTN) Sample Manager
- ACQUITY H-Class
- ACQUITY I-Class
- Blockage in the needle, needle seal, or tubing
- Using salts such as ammonium formate or ammonium acetate in the system
FIX or WORKAROUND
- Disconnect the pump line from port 5 of the inject valve.
- Disconnect the active preheater from port 6 of the inject valve.
- Connect the pump line to port 6 of the inject valve.
- Put LC/MS grade water on A and prime.
- Pump water for at least 30 minutes through the inject valve. If it is still overpressure, try a lower flow rate or warm water.
- Keep increasing the flow rate to 1 mL/min.
- Once confident that blockage is cleared, reconnect the pump and active preheater lines to ports 5 and 6 respectively.
- If the active preheater (APH) is blocked this can be reverse flushed by removing the column and attaching the back end of the APH to port 6 of the inject valve
- Can also try flushing with 50/50 water/organic or straight organic depending on what the blockage is