Hanna Instruments HI 901 - Manual (Page 117)

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 a
good and repeatable result. To fill the burette, follow the next steps and recommendations:
• 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 and a little air zone just above the liquid level at the first filling
movement. The next upward movement will evacuate the entire air. This way no air will be
left in the valve.
Sometimes during the Prime Burette process, slight finger tapping on the tubes is helpful to
evacuate captive air bubbles.
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.