FMI STH/Q User Manual
Page 3
The design of FMI Pumps is unique throughout the
world. Having no valves and only one moving part,
“the piston” makes this design very special. No valves
means that our ceramic pistons and cylinders must
be matched to extremely close fits so that stroke to
stroke accuracy is maintained.
This precision fit requires some general maintenance
rules.
When a pump is allowed to sit idle and dry out, these
dried precipitate can form in the piston/cylinder clear-
ance and cause a pump seizure condition. Upon sys-
tem power up, this seizure can result in either no flow
or at worst a broken piston. So we recommend the
above procedure.
We do not live in a perfect world and accidents do
happen. If your pump seizes try the following pro-
cedures: With the pump in an instrument:
1) Cycle the pump in a back and forth motion (clock-
wise and counter clockwise rotation) at a slow speed
in a high torque mode.
2) Start and stop the pump in an effort to free system.
3) If pump head is accessible try turning the drive
spindle back and forth with your index finger and
thumb.
2.7 Maintenance
With the Pump/Drive Assembly removed from the
instrument but not disassembled (WILL NOT
REQUIRE PUMP RECALIBRATION):
a) Soak the top portion of the pump (PUMP HEAD
ONLY) in a warm water bath for at least 20 minutes.
Then place your index finger and thumb around the
spindle assembly (gold coupling) and gently try to
rotate the assembly back and forth in an attempt to
loosen up the piston.
CAUTION:
Do not force the assembly free if it is
severely frozen as this could result in piston
breakage or pump damage.
IN-ST431-14
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www.fmipump.com
800-223-3388
516-922-6050