Hach EC1000, Инструкция по эксплуатации

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9.2 Troubleshooting the pH Electrode
Table 16 pH Electrode Troubleshooting*
Symptom Probable Cause Corrective Action
The electrode does
not calibrate The wiring to the controller
is incorrect. Check the electrode cable to controller wiring (see Section 5.6.5 Electrode
Wiring). Make sure the wire connectors are contacting the metal wires and
not the wire insulation.
Air in the reference lines. Verify that electrolyte is exiting the electrode reference outlet. Wipe the end
of the electrode dry, and observe the reference outlet tube with the pump
running and the priming tee in the RUN position. A full drop of electrolyte
should become visible within 5 minutes (5 pumps). If a drop does not
appear, purge the system (see
Section 6.3 Purging the System) (also see
Symptom: No electrolyte flow).
pH sensor is internally
shorted. Remove the pH sensor. Verify that two O-rings are being used. Inspect the
O-rings for damage and replace if necessary. Completely dry both the
inside of the socket and sensor assembly. Reinstall. (Refer to
Section 8.1.3
Sensor Replacement).
The calibration procedure
is incorrect. Calibrate again using the correct procedure (refer to Section 2.3
Calibration). Use only Hach buffers when in the AUTO calibration mode. If
other buffers are used, use the MANUAL calibration mode (refer to
Section
2.3 Calibration).
The glass bulb is broken.
(evidenced by reading the
same potential in two
different buffers) Reconfirm that the buffers are different before making this judgment.
Replace the pH sensor bulb.
The controller is defective. Check the controller with the Test Plug provided in the installation kit.
• Turn off the power to the controller.
• Remove the electrode plug connector from the controller and replace it
with the Test Plug.
• Turn on the power to the controller.
• The controller should read from -350 to 350 mV and 40 to 60
°
C if
functioning properly.
If not functioning properly, replace the controller.
Reference has become
poisoned. (This is often
preceded by an E08 error
message which becomes an
INVALID error message.) Replace electrode.
The pH readings
are erratic. Air in reference lines. Verify that electrolyte is exiting the electrode reference outlet. Wipe the end
of the electrode dry and observe the reference outlet tube with the pump
running and the priming tee in the RUN position. If a full drop of electrolyte
does not become visible within 5 minutes (5 pumps), purge the system (see
Section 6.3 Purging the System) (also see Symptom: No electrolyte flow).
Air in the sample line. If a pocket of air passes over or gets trapped at the end of the electrode, the
reading becomes momentarily erratic. This usually is remedied by
reorienting the electrode so that air bubbles do not block the sensor (see
Section 5.5 Installing the pH/ORP Electrode).
The pH reading is being
taken on the reference
electrolyte instead of the
solution being measured.
This is typified by an
oscillating pH reading with a
period of about one minute.
most commonly happens
when testing high purity
water. Orient the reference outlet so it is downstream of the pH glass bulb.
Or, increase the rate of flow past the electrode.
The pH glass bulb is broken Replace the pH sensor. (See Section 8.1.3 Sensor Replacement).
Streaming potential Ground the solution near the electrode (especially in high purity water).