Hanna Instruments HI 903 - Manual (Page 123)

8-7
MAINTENANCE, PERIPHERALS
8.1.6 Burette Preparation (Filling with Titrant)
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
recommendations:
• If necessary, clean the burette and make sure it is empty and dry.
• 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
recommended 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 top.
To avoid the presence of air bubbles inside the burette, make sure to have continuous liquid
flow inside the burette and a little air just above the liquid level during 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.