LaMotte DO 4000 Dissolved Oxygen Meter - Manual (Page 18)

TROUBLESHOOTING
If dissolved oxygen readings appear erratic or unusual, there are several
things which can be checked.
1. Check that the BAT Low indicator is not on. The temperature
function will be the first function to be affected by a low battery.
Replace the battery as soon as possible.
2. There may not be enough sample flowing over the membrane. Try
stirring the sample faster or steadier. Do not stir fast enough to cause
bubbles or splashing.
3. Check the connection between the probe and the meter.
4. The probe may be fouled. Look closely at the membrane; if it looks
dirty or wrinkled it should be replaced. See Cleaning the Probe on
page 20.
5. If calibration is not successful after following Step 4, adjust the
“Slope adjustment pot” according to instructions on page 15.
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