Troubleshooting - Hach 1720E User Manual

Troubleshooting

Table 5
corrective actions.
Sensor Warning Possible Cause
Lamp burned out
Lamp unplugged
Bad Lamp +12 V connection loose at controller
Dislodged lamp
Bad circuit board in turbidimeter head
Photocell coated/dirty
Photocell wires disconnected
Photocell broken/cracked
Low Signal
Lens coated/dirty
Obstructed light path
See Bad Lamp causes above
Improper wiring at controller
Turbidimeter head cable shortened to
improper length
Bad System Voltage
Fluctuation in voltage
Bad circuit board in turbidimeter head
Fluctuation in voltage
A/D Converter Timeout
Bad circuit board in turbidimeter head
Light Leak—Turbidimeter head not on
turbidimeter body or calibration
cylinder during Power Up or Zero
Electronics
Light Leak—Turbidimeter head not
High Dark Counts
properly aligned on the turbidimeter
body or calibration cylinder during
Power Up or
Zero Electronics
Photocell broken/cracked
Table 6
Table 6 Additional Malfunctions Not Recorded in the Event Log
Symptom Possible Cause
Continuous Underrange The calibration standard was either
improperly prepared or was unstable at
the time the calibration was accepted.
Continuous Overrange The calibration standard was either
(100 NTU) improperly prepared or was unstable at
the time the calibration was accepted.
Erratic Readings Inadequate bubble removal from sample Verify the accuracy of calibration standards and
28
presents sensor warnings displayed in the Event Log, possible causes, and
Table 5 General Troubleshooting
presents additional malfunctions which may not be recorded in the Event Log.
Corrective Action
Replace the lamp. See section 6.4.3 on page
Restore connection
Restore connection
Reinstall lamp
Contact the Customer Service Department.
See section 6.4.1 on page 24.
Contact the Customer Service Department.
Reconnect wires
Replace photocell
Contact the Customer Service Department.
Clean the lens using isopropyl alcohol and a cotton swab.
Remove obstruction
See Bad Lamp corrective actions above
Refer to section 3.1 on page
Contact the Customer Service Department.
Turn instrument power off and back on.
Contact the Service Department
Turn instrument power off and back on.
Contact the Customer Service Department.
Make sure the turbidimeter head is on the turbidimeter
body and properly aligned and repower instrument or
perform ZERO ELECTRONICS in the CALIBRATION
MENU.
Make sure the turbidimeter head is properly aligned and
repower instrument or perform ZERO ELECTRONICS in
the CALIBRATION MENU.
Contact the Customer Service Department.
Corrective Action
Verify the accuracy of calibration standards and
recalibrate the instrument. See Low Signal in
Verify the accuracy of calibration standards and
recalibrate the instrument.
recalibrate the instrument.
Increase the signal averaging time to a longer interval.
Make sure the Bubble Reject feature is turned on.
Slow the flow of sample into the instrument.
25.
7.
Table 5.