Instructional manual- HBPH-MK2
– UK-004
Page 7
Replacement of Salt Bridge
1.
If the system cannot be calibrated after cleaning the probe, it may be necessary to replace the
standard cell solution and/or the salt bridge. A salt bridge kit is available from HB Products for this
purpose.
2.
Hold the probe vertically electrodes up. Remove the used salt bridge. The salt bridge is a
hexagonal-
shaped capsule that can be removed using a #3 Phillips screwdriver. ½” wrench or pliers
can also be used.
3.
Discard the used salt bridge.
4.
Dispose of the used solution inside the bridge chamber and rinse with pH 7 solution or distilled
water.
5.
Refill the chamber with a reference solution supplied with the salt bridge, up to the tip of the
electrode inside the chamber. DO NOT OVERFILL. It is important to leave space for the salt bridge
thread and a small amount of air.
6.
Screw the new salt bridge into the cavity until finger tight. If needed, use a #3 Phillips screwdriver
to make sure that the salt bridge edges are aligned with the front of the probe face.
Troubleshooting
A sensor that is not functioning properly will output a current that is out of range of the specifications
listed in Checking Sensor section.
The change in output with calibration standard constitutes the span. For a pH probe, the span between
pH 4 and pH 7 or between pH 7 and pH 10 should be between 2.75 and 3.5 mA.