14
HTEC-500
Error 3
The computer on the HPLC pump unit is programmed to display error 3 when one of the check valves
does not work properly. If the pressure sensor detects a rapid pressure decrease and cannot return the
pressure to the previous level within 12 rotations of the motor, error 3 is displayed. If you are running the
pump for maintenance, please switch off the pulse free mode.
Error 3 may occur for the following reasons (Treatments are also described below):
A. The tubing connection is not good. There is a leak somewhere in the high pressure zone between
the pump piston and the separation column. Check if there is any leak in the flow line. Typically, the
connection at an injector valve or at the column inlet may become disconnected. If you find it has
been disconnected, please re-connect it. A pressure reading of more than 150 MPa will lead to the
disconnection of fittings. Please check that your column is not too old and if the precolumn is
clogged.
B. Air needs to be removed from the pump. See chapter 8, page 11.
C. If air gets trapped in the pump frequently, make sure the connections are tight enough, the tubings
are not damaged and the elution degassing system is working properly (see also chapter 6,
page 7). The cause of resistance in the pumping system can be either that the mobile phase bottle
is at a lower position compared to the HTEC-500 or an inline filter is present upstream of the pump
(typically a tubing anchor filter in the mobile phase bottle is used). Check that the mobile phase
bottle is on the same level as the HTEC-500. Please remove the filter if you have one.
D. One of the check valves has lint, dust or something inside. This problem happens more frequently in
the inlet check valves located at the bottom of the pump head. Replace only the inlet check valve
having the problem by the method described below. If the problem persists even after this
exchange, the outlet check valve may be the problem.
To find out which side of the pump has the problem perform the following steps:
• Keep the mobile phase level in the bottle at the same level or a few inches lower than the inlet
check valve.
• Release both the left and the right side of the hex nut that holds the
tubing at the outlet check valves (see fig. 13) and see if the mobile
phase comes up and at what speed it comes up at. When one of
the inlet check valves has failed, the mobile phase on that side
should come up significantly slower than the other side or may never
come up. You can also run the pump with the pulse free mode off
to check if the solution flows or not.
• Replace the failed inlet check valve with a new one (Inlet check valve, catalog #HT-IV)
• Alternatively, the failed check valve can be cleaned but very detailed work is required to clean it
well. If you are not good at detailed work, simply exchange the valve with a new one. The check
valve structure is shown in Fig. 15. Please prepare 50 ml acetone in a 100 ml beaker. Then screw in
a stop-fit (a plug type fitting) into the valve and push out the inside parts into the acetone
(see Fig. 14). Clean all the parts with acetone and assemble it back to its original structure. Always
use clean forceps to pick up each part and do not touch them with your fingers.
Fig. 13
