33
HTEC-500
Appendix. A
Piston and Piston Seal Exchange
Note: Please read each step completely before you proceed. Also, please remember the
order and orientation of all parts as you remove them. This helps to avoid having to
disassemble the pump and risk breaking or damaging the piston.
1. Remove the PEEK tubing at the inlet and the
outlet of the check valves. Unscrew the hex
nut at the outlet by using a wrench (8 mm).
Using your fingers, unscrew the tuff connector
at the inlet.
2. Unscrew the two nuts on the pump head by
using an Allen wrench.
3. Remove both nuts.
4. To remove the pump head, slowly and
carefully pull the pump head directly towards
you without twisting it. Vertical rotation as
piston becomes axis. Other movement in
other directions will break the piston that lies
inside.
5. The piston will now be exposed. As you can
see the piston is very fragile. Please be very
careful when handling it. Please look at the
surface of the piston and note if the piston is
worn or not. Actually, it is difficult to see the
quality without removing the piston from the
body. To remove the piston, in order to
replace it or to examine it more carefully,
please continue to the next step. If you find
the piston is in good condition, and would just
like to change the piston seal, please skip to
step 11.
