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Main
Office
10940 Beaver Dam Rd
Hunt Valley, MD 21030
Ph: 410-666-3200
Fx: 410-666-3631
Central VA
Office
10993 Richardson Rd #13
Ashland, VA 23005
Ph: 804-752-3450
Fx: 804-752-3451
Tidewater
Office
4402 Edwin Rd
Portsmouth, VA 23703
Ph: 757-686-1777
Fx: 757-686-9333
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Application
Note
Troubleshooting
Ground Loops in pH Systems
Courtesy of GLI / HACH
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1. Clean
the sensor: Remove the sensor from the process and rinse
it with clean, warm water. Then soak the sensor in a
mild soap solution for 2-3 minutes. Using a soft bristle
brush, scrub the
entire measuring end of the sensor, taking care not to
scratch the glass measuring
electrode. Rinse in clean, warm water. If the sensor is
in a process above 7 pH, it is advisable to soak it 4 -
5 minutes in a weak acid solution (hydrochloric
recommended). Place the sensor back in the soap solution
for 2 - 3 minutes. Rinse it in clean warm water.
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| 2.
Calibrate the sensor
and instrument with pH buffers. (See analyzer manual for
correct procedure). If calibration is successful,
maintenance is now complete. If calibration cannot be
accomplished, you may need to replace the standard cell
solution and salt bridge. |
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| 3.
To remove the salt bridge: Hold the sensor in an upright
position and turn the salt bridge counterclockwise with
a pliers, 9/16 inch socket wrench or nut driver. Take
care not to damage the glass measuring electrode. |
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4.
Pour out the aged standard cell solution.
Thoroughly flush the standard electrode chamber with
fresh standard cell solution. |
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5.
Fill the standard electrode chamber to the
top of the thread with fresh standard cell solution. |
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6.
Install the new salt bridge, making sure the O-ring is
intact. Turn the salt bridge clockwise until finger
tight. Then tighten with pliers, socket wrench, or nut
driver approximately 1/4 turn.
Do not over tighten. |
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