Hanna Instruments HI 902 Color, Quick Start Manual

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9-7
MAINTENANCE, PERIPHERALS
9.1.6 Burette Preparation (Titrant Filling)
Before starting a titration, the burette must be properly filled with titrant in order to obtain an
accurate and repeatable result. To fill the burette, follow the next steps and recommenda-
tions:
• If necessary, clean the burette and make sure it is empty.
• From the main screen press .
• Highlight
Prime Burette option and press
.
• Enter the number of times the burette needs to be rinsed (minimum three rinses are
recommend allowing air bubbles to be evacuated).
• Press .
• Insert the aspiration tube into the titrant bottle only when the piston is going down
and has reached about ¼ from the upper end.
To avoid the presence of the air bubbles inside the burette, make sure to have a continuous
liquid flow inside the burette. A little air just above the liquid level at the first filling is
normal. The next filling will evacuate all of the air; no air will be left in the valve.
Sometimes during this process, slight finger tapping on the tubes is helpful to remove any
residual air bubbles from the tubes.
If air bubbles are still present:
• Remove the aspiration tube from the titrant bottle.
• Repeat burette preparation procedure.
• If no success, clean the burette again.
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