Maintenance And Cleaning - GF Signet 276 Differential Series Operating Instructions Manual

Response Time/Stability
Response time and stability are aff ected by the condition of the pH glass measuring surface (for an ORP electrode, the platinum
surface),the reference junction and the reference solution. Electrodes may sometimes be restored to acceptable levels by cleaning the
measuring surface and reference junction.
Electrode mV values should remain stable ± 3 mV. Conditions that may cause fl uctuations are:
• Electrode coating
• Clogged reference junction
• Ground fault: If proper operation is observed in the beaker, but readings are unstable in the application, a ground fault may exist.
• Using instrumentation with isolated inputs and outputs may restore stable operation.
• Solution grounding may also restore stable operation.

Maintenance and Cleaning

276X Series Diff erential Electrodes
Diff erential electrodes have a replaceable salt bridge and the
electrolyte chamber can be refi lled. The electrolyte chamber
should be full. If any fl uid is audible when shaken, the chamber
should be refi lled. Refi ll the electrolyte chamber when the
electrode off set exceeds 40-45 mV. Replace the salt bridge
when performance becomes sluggish or if the output is erratic
or inaccurate.
Replacing the Salt Bridge
Parts Required: Salt Bridge (order number 3864-0001) and
Diff erential Reference Solution
(order number 3864-0002)
Tools Required: Small pliers
Procedure:
1. Remove sensor from mounting.
2. Hold upside down and unscrew salt bridge using a pair of
small pliers. Be careful not to damage the glass bulb!
3. Drain the depleted reference solution and dispose of
properly.
4. Fill reference chamber with fresh reference solution
(approx. 30 ml).
5. Replace salt bridge and screw fi nger tight. Solution will drip
out while screwing in salt bridge.
Use pliers to turn approximately ¼ turn past fi nger-tight.
6. Perform calibration (standard and slope) before returning
the system to service.
NOTE:
The refi llable electrolyte chamber in 276X series
diff erential electrodes may leak during storage and
shipping. Check the fl uid and refi ll before installation
if necessary.
10 Signet 275X, 276X, 2777X Series pH and ORP Electrodes
WARNING!
Wear appropriate eye, face, hand, body, and
respiratory protection when using chemicals or
solvents.