Section 8 Electrode And Pump Maintenance; Electrode Maintenance; General Electrode Maintenance; Removing Existing Electrode - Hach EC1000 Instruction Manual

SECTION 8 ELECTRODE AND PUMP MAINTENANCE

8.1 Electrode Maintenance

8.1.1 General Electrode Maintenance

8.1.2 Removing Existing Electrode

Note: Avoid permanent
electrode damage by
shutting off the EC1000
Analyzer before
disconnecting the
electrode at the
quick disconnect.

8.1.3 Sensor Replacement

Note: Pump Module is not used with the Industrial pH Electrode (Cat. No. 48276-00).
The measuring glass portion of the electrode is not greatly affected if the unit is stored dry
for short periods of time. The electrode will rehydrate upon reinstallation, however, it may
take five minutes or more to rehydrate completely, depending on the sample conditions.
For longer periods of time outside the sample stream, store the reference portion of the
electrode in Electrode Storage Solution (Cat. No. 50301-49). If the reference junction
dries out, rehydrate by soaking in a pH 4 buffer with KCl for about eight hours. If the
junction is not completely rehydrated, the electrode will suffer slow response times and a
possible inefficiency of slope.
Handle the electrode carefully to protect the pH-sensitive membrane. One way to protect
the membrane is to have the protective cap in place whenever the electrode is removed
from the process stream. If the electrode is to remain out of the process stream for more
than on hour, make sure the cotton in the protective cap is saturated with Electrode Storage
Solution (Cat. No. 50301-49). If a conditioning solution is not available, use pH 4.01 or
7.00 buffers or tap water.
1. Turn off power to the EC1000 Analyzer.
2. Turn off power to the electrolyte pump.
3. Disconnect the electrode cable and reference tubing from the electrode body.
4. Unscrew the electrode from the Hach Process pH/ORP Cell Holder, and remove the
bushing or collar from the old electrode.
5. Place a new sensor assembly onto the new electrode body, as described below.
6. Place the bushing or collar on the new electrode so that it is positioned in the same
way as it was on the previously used electrode.
7. Connect the electrode cable.
8. Connect the electrode reference tube to the electrode check valve with the
compression nut and ferrule. Finger tighten only.
The replaceable sensor assembly (pH or ORP) is screwed into the threaded hole on the
bottom of the electrode body (see Figure 24). Be sure both the inside of the hole and the
sensor are dry before attaching. A cotton swab is included with the sensor to clear the
hole of any moisture and debris. Two o-rings are required to make the seal. Use the
plastic sensor wrench to tighten the sensor assembly. The plastic loading nut of the sensor
assembly should be flush with the end of the electrode body when properly seated.
1. With the sensor wrench, remove the old sensor. Clear debris and old o-rings from
the socket using a cotton swab (make sure the o-rings have been removed from
the electrodes).
2. Rinse the sensor socket with deionized water and dry it with a clean cotton swab.
3. Rinse the pin end of the new sensor with deionized water and carefully dry it with the
cotton swab.
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