Emerson Rosemount 499ADO, Quick Start Manual

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5 Maintenance
Periodic maintenance and cleaning are required for best performance of the sensor.
Generally, the membrane and fill solution should be replaced every four to six months.
Sensors installed in harsh or dirty environments require more frequent maintenance. The
optimum maintenance frequency is best determined by experience.
WARNING!
PRESSURIZED SPRAY INJURY
Before removing the sensor, be absolutely certain that the process pressure is reduced to
0 psig and the process temperature is lowered to a safe level!
5.1 Cleaning the membrane
Keep the membrane and sensor tip clean and free from dirt. Clean the membrane with
water sprayed from a wash bottle. Use a soft tissue to gently wipe the membrane.
5.2 Replacing the electrolyte solution and
membrane
WARNING!
HARMFUL SUBSTANCE
Fill solution may cause irritation. May be harmful if swallowed. Read and follow manual.
Procedure
1. Unscrew the membrane retainer.
2. Remove the membrane assembly and O-ring.
See Figure 1-1 .
3. Hold the sensor over a container with the cathode pointing down.
4. Remove the fill plug.
5. Allow the electrolyte solution to drain out.
6. Inspect the cathode.
a. If it is tarnished, clean it by gently rubbing in the direction of the existing
scratches (do not use a circular motion) with 400-600 grit silicon carbide
finishing paper.
b. Rinse thoroughly with water.
7. Remove the old pipe tape from the plug.
Maintenance
Quick Start Guide 19