Thermo Scientific EASY-nLC 1200 Troubleshooting And Maintenance Manual page 198

7
Troubleshooting
Troubleshooting a Pump That Fails the Flush Air Script
176 EASY-nLC 1200 Troubleshooting & Maintenance Guide
5. Check whether the tubing that connects the pressure sensor to the valve is blocked as
follows:
a. Reconnect the solvent line to port 1 of the valve.
b. Disconnect the fitting connected to the top of the pressure sensor.
c. Pipette solvent into the port on the top of the pressure sensor.
CAUTION Be careful not to spill solvent on the PCBs.
• The LED panel cover for each pump protects the PCB from accidental
contact when the instrument's right side panel is removed. However, the
cover does not form a waterproof seal with the pump body so that the PCBs
are exposed to solvent leaks from above.
d. Run the Purge Solvent script and check that the pump is aspirating solvent through
the pressure sensor.
e. Depending on whether solvent is aspirated, do one of the following:
• If the pump does not aspirate solvent, go to
• If the pump aspirates solvent, the tubing that connected the pressure sensor to
the valve is damaged. Do the following:
i. Disconnect this tubing from the valve, and install a new solvent line.
ii. To confirm that installing new tubing fixes the problem, run two iterations
of the Purge Solvent script. Then, run the Flush Air script with a threshold
of 12 µl.
6. To determine if the problem is in the pump, do the following:
a. Reconnect the solvent line to the top of the pressure sensor and tighten the fitting.
b. Disconnect the solvent line from the pump head.
c. Pipette the appropriate solvent into the port in the pump head (see
page 79).
d. Run the Purge script and check that the pump is aspirating solvent from the pump
head into the pump.
• If the pump does not aspirate solvent from the pump head, the problem is in the
pump.
• If the pump does aspirate solvent from the pump head, replace the tubing that
connects the pump to its pressure sensor.
7. If the problem is in the pump, verify that the piston is not dirty, broken, or scratched and
replace the piston seal as described in
step 6.
"Maintaining the Syringe Pumps"
Figure 63 on
on page 70.
Thermo Scientific