MODEL 396R pH/ORP | SECTION 6.0 |
| MAINTENANCE |
SECTION 6.0
MAINTENANCE
6.1Maintenance. The Model 396R Sensor is a dis- posal type sensor and therefore requires minimum maintenance. The sensor should be removed from the process periodically and checked in buffer solutions. If the sensor will not calibrate, refer to your analyzer/transmitters instruction manual for proper test procedures. If the sensor has failed, it should be dis- carded and replaced.
6.2Sensor Removal. Please refer to the appropriate paragraph for instructions regarding removal of the sensor for periodic maintenance.
6.2.1 Retractable Version.
4.Close the ball valve slowly. If there is resistance, the valve may be hitting the sensor. Double check that the sensor has been retracted to the retrac- tion stop collar.
WARNING 
Before removing the sensor from the ball valve, be absolutely certain that the ball valve is fully closed. Leakage from the male connector threads may indicate that the male connector is still under pressure. Leakage through a partially open valve could be hazardous, how- ever with the ball valve closed, some residual process fluid may leak from the connector's pipe threads.
WARNING 
System pressure may cause the sensor to blow out with great force unless care is taken during removal. Make sure the following steps are adhered to.
A. Model 396R-21 (21” tube)
1.Be certain system pressure at the sensor is below 64 psig (542 kPa) before proceeding with the retraction. It is also recommended that the per- sonnel wear a face shield and have a stable foot- ing. Refer to Figure
B. Model 396R-25 (36” tube)
2.Be certain that pressure at the sensor is below 35 psig (343 KPa) before proceeding with the retrac- tion. It is also recommended that the personnel wear a face shield and have a stable footing. Refer to Figure
(B) of the process end male connector (A).
5.The Male Connector Body (A) may now be com- pletely unthreaded from the reducing coupling and the sensor removed for servicing.
CAUTION
If the male connector leaks during insertion or retrac- tion, replace the
6.3pH Electrode Cleaning. If the electrode is coated or dirty, it may be cleaned as follows:
1.Remove the sensor from process as instructed in Section 6.2.
2.Wipe the glass bulb with a soft, clean, lint free cloth or tissue. If this does not remove the dirt or coating, proceed to step 3. If the sensor appears to be clean, go to step 5.
3.Wash the glass bulb in a strong detergent solution and thoroughly rinse with tap water. If the bulb still appears to have a coating, proceed to step 4.
CAUTION
Do not remove nut at this time.
3.When the hex nut is loose enough, slowly ease the sensor back completely until the retraction stop collar is reached.
CAUTION
Failure to withdraw the sensor completely may result in damage to the sensor when the valve is closed.
CAUTION
The solution used in the following step is an acid and should be handled with care. Follow the directions of the acid manufacturer. Wear the proper protective equipment. Do not let the solution come in contact with skin or clothing. If contact with the skin is made, immediately rinse with clean water.
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