Nova-Tech DO 700 - Manual (Page 31)

PROBLEM CAUSE SOLUTION
CAL % calibration value is not
acceptable.
Electrode is disconnected
or failing. Check electrode connections.
Check that correct DO unit is
selected & repeat cal procedure.
Service electrode.
Reset meter.
Replace electrode.
CAL ppm or mg/L calibration is
attempted when the factory
calibrated absolute value is
below 2.00 Use concentration calibration
solution higher than 2.00.
Check electrode connections.
Check that correct DO unit is
selected & repeat cal procedure.
Service electrode.
Reset meter.
Replace electrode.
Slow
response or
unstable
readings External noise pickup or
induction caused by
nearby electric motor
Insufficient electrolyte in
probe
Air bubbles near sensor
Dirty or damaged probe
Probe not deep enough in
sample
Broken probe
Remove or switch off interfering
device
Fill probe with electrolyte & / or
replace pre-assembled cap
Stir or tap probe to remove
bubbles, reduce stirring
Clean the probe and re-calibrate
Submerse sensor cap into sample
Replace probe or membrane
25