Hach FH950 Basic User Manual page 20

1. Push the meter power button until an audible beep is heard.
The meter does a self test and the display shows the results. If the meter fails the self-test, the
display shows FAIL next to the failed parameter. If the sensor fails, attach a different sensor if
available.
2. When the self test is complete, push OK to go to the Main Menu.
3. To de-energize the meter, push the power button again. In the Confirmation screen, select Yes
and push OK.
If the portable meter becomes unresponsive, push and hold the power button for more than
3 seconds to force the power off. Do not force off the power in normal operation or when the file
access icon is visible.
6.1 Instrument self test
The meter does a diagnostic self-test when energized. After the self-test is complete, the display
shows the self-test results. Push OK to go to the Main Menu.
If the meter fails the self-test, the display shows FAIL next to the parameter in question. If the sensor
fails, attach a different sensor if available.
6.2 Sleep mode
The meter backlight goes dim after 30 seconds of no activity and goes into sleep mode after
60 seconds of no activity. These actions do not occur if the meter is in real-time mode or while the
meter is measuring. After 30 minutes in sleep mode, the meter power goes off.
To cancel the sleep mode, push any key. The display brightness goes back to the normal level and
all keys go back to their normal functions.
Section 7 Maintenance
7.1 Clean the sensor
Chemical exposure hazard. Obey laboratory safety procedures and wear all of the
personal protective equipment appropriate to the chemicals that are handled. Refer to
the current safety data sheets (MSDS/SDS) for safety protocols.
Clean the sensor when unexpected increases or decreases in flow or level trends occur and after
use in sandy or muddy waterways.
For heavy contamination, soak the sensor in clear water for a few minutes to help make the
contamination easy to remove.
Disconnect the sensor from the meter before it is cleaned. Use only solutions listed as acceptable in
Table 3 to clean the sensor. For sensors with a pressure cell (i.e., velocity plus depth sensors), make
sure the holes for the pressure cell chambers are washed out and clear of contamination. Rinse the
sensor with clean water before re-attaching the sensor to the assembly.
Table 3 Acceptable and unacceptable cleaning solutions
Acceptable
Dish detergent and water
Window cleaner
Isopropyl alcohol
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W A R N I N G
Do not use
Concentrated bleach
Kerosene
Gasoline
Aromatic hydrocarbons