Troubleshooting the Rheodyne 7725i Manual Injector 125
Rotor seal leakage
(liquid dripping
between stator and
stator ring, or from
needle port or vent
tube)
Pressure adjusting
screw loose
Tighten pressure adjusting screw. Refer to
Section 4.4.4, Tightening the Pressure
Adjusting Screw.
Scratches on rotor seal Replace rotor seal. Refer to Section 4.4.3,
Rotor Seal Leakage.
Needle seal leakage Syringe needle OD
smaller than needle
seal, reducing sample
loading accuracy
Try another syringe needle. Gently push on
plastic needle guide to deform Teflon sleeve
to provide a better needle fit. See
Section 4.4.1, Tightening the Needle Seal.
Plugged valve passages
or vent lines
Unfiltered eluent or
sample, or buffer solu-
tions crystallized in
vent lines
Remove the stator and clean the passages
with a wire of 0.005-inch maximum
diameter.
If the valve passage remains plugged,
disconnect the tubing at the vent valve
outlet. If this clears the passage, replace the
tubing. If the passage remains blocked,
disconnect the compression screw at the
vent valve inlet. If this reduces the pressure,
rebuild the vent valve (see the documenta-
tion included with the 7725i injector.
Ensure eluent and sample are properly
filtered to prevent additional precipitation.
Flush the flow passages and vent lines with
water after use of salt solutions. Salt solu-
tions should not sit stagnant in the valve
overnight or for long periods of time.
Gradient does not start Position sensing switch
is not sending the inject
signal to controller
Replace the position sensing switch as
described in Section 4.4.2, Replacing the
Position Sensing Switch.
Table 6-2 Rheodyne 7725i Injector Troubleshooting (Continued)
Symptom Possible Cause Corrective Action
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