Troubleshooting - YSI PRO20 User Manual

T R O U B L E S H O O T I N G
ERROR MESSAGES
Symptom
Instrument will not calibrate;
instrument displays "Calibration
Over", "Calibration Under", or
"Unstable Reading"
calibration.
Instrument will not turn on, a
battery symbol
"Critical Shutdown" displays on the
screen.
Barometer reads
Dissolved Oxygen
Temperature display Over/Undr,
and pressing Cal key results in a
Barometric Pressure Over/Undr
message.
1) Verify barometer reading
2) Verify correct sensor and membrane
during
3) Calibration sleeve may not be 100%
4) Ensure adequate sample movement if
5) Allow sufficient stabilization time for
6) Replace membrane and electrolyte
7) Clean sensor electrodes
8) Return system for service
1) Low battery voltage, replace batteries
appears, or
2) Batteries installed incorrectly, check
3) Return system for service
1) Barometer failure, return system for
over/under,
and
33
Possible Solution
type selection in the System Setup
menu.
water saturated, ensure sponge is
moisten
performing mg/L or ppm calibration
dissolved oxygen and temperature
AND wait at least 3 seconds before
confirming a DO % or DO %Local
calibration
battery polarity
service