Yokogawa PH72 Personal pH/ORP Meter - Manual (Page 61)

IM 12B03D02-01E 7-4
7. Troubleshooting
(3) Err3 Abnormal slope or calibration temperature
Appears during calibration.
In the Model PH72 Personal pH/ORP Meter standard solution data (NIST and US) are
preprogrammed. During automatic calibration the meter recognizes standard solutions
being used based on these data. If standard solutions other than the preprogrammed ones
are used, an Err3 message will appear. It will also appear if the slope is outside the range
of 65 to 125%.
Possible Causes:
• Defective standard solutions.
• Dirty electrode.
• Clogged liquid junction.
• Insulation failure in electronics.
• Outside calibration temperature range.
• Improper manual temperature setting.
Corrective Actions:
• Use properly prepared standard solutions. (See Chapter 4.)
• Remove dirt or deposits from the electrode and liquid junction. (See Section 6.2.)
• Remove stain or moisture from the connectors. (See Section 6.6.)
• Perform calibration within the calibration temperature range.
• Set the temperature of the solution used manually and correctly. (See Section 5.3
(2).)
(4) Err4 Out of measuring range
Appears during measurement.
The Model PH72 Personal pH/ORP Meter can measure the pH value of a solution in the
range of 0 to 14 pH. If the pH value of the solution being measured is significantly
outside this range (-2 pH or lower and 16 pH or higher), an Err4 message will appear. It
will also appear if the electrode is dirty or has dried out. When a new sensor is used for
the first time, an Err4 message may appear. This is due to low hydrophilic property a
new sensor may have.
Possible Causes:
• Solution pH is significantly outside the measuring range of 0 to 14 pH.
• Dry electrode.
• Dirt or deposits on electrode.
Corrective Actions:
• Immerse the sensor in water for 1 to 2 hours or longer to rehydrate. (See Section
6.4.)
• Remove dirt or deposits from the sensor. (See Section 6.2.)