Emerson Rosemount 398R, Reference Manual

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B. Rosemount 398R-25 and 398RVP-25 (36” tube)
2. Be certain that pressure at the sensor is below 35 psig before proceeding with the
retraction. It is also recommended that the personnel wear a face shield and have
a stable footing. Refer to Figure 6-1. Push in on the cable end or the top of the
junction box and slowly loosen the hex nut (B) of the process end male
connector (A).
3. When the hex nut is loose enough, slowly ease the sensor back completely until
the retraction stop collar (mechanical safety stop) is reached.
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 Double check that the sensor has been retracted to the retraction stop collar.
5. The Male Connector Body (A) may now be completely unthreaded from the
reducing coupling and the sensor removed for servicing.
6.3 Cleaning Procedures - pH Sensors
To remove the sensor from the process piping, follow the instructions in Section 6.2.
32 Maintenance
Maintenance Reference Manual
February 2019 00809-0100-3098
Do not remove nut at this time.
CAUTION
Failure to withdraw the sensor completely may result in damage to the sensor when the valve is closed.
CAUTION
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, however with the ball valve closed, some
residual process fluid may leak from the connector's pipe threads.
If the male connector leaks during insertion or retraction, replace the O-ring (PN 9550167) in the male
connector A.
CAUTION
Only persons thoroughly familiar with the procedure for diluting concentrated hydrochloric acid should
prepare the solution. Dilute the acid in a fume hood or in a well-ventilated area. Point the acid bottle away
from people when opening it. Wear appropriate safety equipment, including chemical goggles and gloves.
Do not let acid touch the skin or clothing. If acid solutions contact the skin or eyes, rinse thoroughly with
water. Seek medical assistance.
CAUTION