Flow Through Needle (FTN) ACQUITY H-Class or I-Class system with pump overpressure error message - WKB9936

SYMPTOMS

• Pump overpressure
• System overpressure error
• Pressure is normal when FTN is switched from inject to load on interactive control

ENVIRONMENT

• Flow Through Needle (FTN) Sample Manager
• ACQUITY H-Class
• ACQUITY I-Class

CAUSE

• Blockage in the needle, needle seat, or tubing

FIX or WORKAROUND

1. Disconnect the pump line from port 5 of the inject valve.
2. Disconnect the active preheater from port 6 of the inject valve.
3. Connect the pump line to port 6 of the inject valve.
4. Put LC/MS grade water on A and prime.
5. Pump water for at least 30 minutes through the inject valve. If it is still overpressure, try a lower flow rate or warm water. 
6. Keep increasing the flow rate to 1 mL/min.
7. Once confident that blockage is cleared, reconnect the pump and active preheater lines to ports 5 and 6 respectively. 

ADDITIONAL INFORMATION

• 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