3M MP220 Installation Guide - Page 11

Problem Solving Err 1 - offset value (E ) out of range 0 Check correct buffer is used. Check mV reading for pH 7 buffer is 0 ± 30 mV. If it is not, clean or replace the electrode. Err 2 - slope out of range Slope less than 85%, or not calculable. Electrode needs cleaning, conditioning or replacing. Check correct buffers are used. Slope more than 105.0%. Check calibration buffers. NOTE: Where 0 mV/pH unit = 0%, and 59.16 mV/pH unit = 100% (at 25°C) Err 3 - pH buffer outside temperature limits pH buffers must be between 5°C and 50°C for accurate calibration. . Displayed (out of range) Check electrode is connected and immersed in sample. Check wetting cap is removed. Data Entry Errors Date flashes and reverts to previous setting - invalid date entered. Entered temperature value changes to -5.0 or 105.0 - the meter will not accept values outside this range. Dashes displayed instead of buffer value during calibration buffer set up - that buffer has already been selected for a cal point. Cal points must have different values. 11