Shutdown; Troubleshooting - Hach POLYMETRON 8810 User Manual

Maintenance and Troubleshooting

7.1.5 Shutdown

7.2 Troubleshooting

Malfunction
Irregular sample volume in the
measurement cell
High fluctuation of
results
Regular sample volume in the
measurement cell
34
If needed, clean the exterior of the instrument with a moist cloth and a mild soap solution.
Never use cleaning agents such as turpentine, acetone or similar products to clean the
instrument, including the display and any accessories.
Stopping the measurement cycle
Select STOP in the main menu and press Enter. The message stopped is displayed.
Short shutdown (e.g. weekend)
Select STAND BY in the main menu and press Enter to put the system in a defined
standby condition. The measurement chamber is drained, rinsed, and refilled with rinse
water.
Prolonged shutdown
If the system is shut down for a long period of time the electrodes must be cleaned and
the measurement chamber rinsed. It is preferable to then remove the electrodes and
store them in a buffer solution until the system is restarted. Under no condition must the
electrodes be left in an empty measurement chamber as this will cause them to dry out
and become damaged. Finally, turn the power off.
Possible cause
Siphon working intermittently
because of erratic sample
flow (rinse water when
diluting)
Volume of sample is too low
Drain valve
Drainage
Air bubbles in the reagent
tubing
Sample conditioning
Corrective action
Check sample flow > 40 L/minute
Check air pressure 4 - 7 bars
Make sure the siphon drain tubing is
as short, direct and as vertical as
possible
Make sure the top of the overflow is
higher than the top of the siphon by
about 2 cm
Check the sample time parameters
Check for leaks and dirt on the
valve seal
Check the drainage is free flowing
Check the tube connections
Regular maintenance
Check all the tubing
Check the sample conditioning
parameters