Error "Sample pressure sensor h/w fault (xxx.x)" with Sample Manager - Flow Through Needle - WKB125649

SYMPTOMS

• Warning: Drawing sample rate excessive (-16.8)
• Error: Sample pressure sensor h/w fault (202.2)
• System pressure is much higher in the inject position

ENVIRONMENT

• ACQUITY UPLC Sample Manager - Flow Through Needle
• ACQUITY UPLC H-Class
• ACQUITY UPLC H-Class Bio
• ACQUITY UPLC H-Class PLUS
• ACQUITY UPLC H-Class PLUS Bio
• ACQUITY UPLC Sample Manager - Flow Through Needle PLUS (SM-FTN PLUS)

CAUSE

The needle is clogged or restricted by mechanical damage. The tip can be damaged by a crash. When sample is aspirated, the negative pressure is too high. When the injection valve switches from inject to load, the sample pressure becomes too high.

FIX or WORKAROUND

1. Power-off and power-on to clear the error.
2. Set a low flow and attempt to flush the needle manually (remove from needle carriage if necessary).
3. Back-flush the needle if standard flushing does not work (WKB116842).
4. Back-flush the seat port (as above) if the error does not clear.
5. If the error persists, replace the needle, seal, and seat port.

ADDITIONAL INFORMATION

Some methods perform injections of samples that are not compatible with the mobile phases they use. This can cause precipitation within the tip of the needle on aspiration. The best method to remove this is back-flushing because there is a short distance for the blockage to travel before it leaves the system.