Metrohm 739 Exchange unit - Manual (Page 39)

6. Cleaning
6.3013.XXX and 6.3014.XXX Exchange Units, 8.110.1346
39
6. Cleaning
The Exchange Unit has to be emptied and cleaned only if the
reagent caused any precipitation or if you wish to fill the Ex-
change Unit with a different reagent. Proceed as follows:
1. Empty the Exchange Unit as much as possible.
2. Set Dosimat/Titrino in zero position.
3. Remove the tubing connections of the reagent bottle and of
the buret tip.
4. Remove light protection (thermostat jacket).
5. Undo the screw nut of the glass cylinder.
6. Empty cylinder completely using the 6.2739.010 key and
carefully pull out the piston.
7. Clean all parts. Take care that no reagent remains in the
threaded holes.
8. Lightly grease piston at the side with 6.2803.010 grease.
Wipe off leading edge to ensure that the reagent does not
come into contact with the grease.
Do not grease piston for pipetting.
9. Reassemble Exchange Unit.
Tighten the tubing connection first at the glass cylinder, then
at the stopcock.
7. Accuracy
Accuracy data:
Buret volume V
nominal
mL
Abs. error rel. to
V
nominal
mL
Reproducibility
mL
1 0.003 0.001
5 0.015 0.005
10 0.02 0.01
20 0.03 0.01
50 0.05 0.04
Checking accuracy:
Dosing accuracy - Application Bulletin No. 238
Potentiometric titrations - Application Bulletin No. 252
KF titrations - Application Bulletin No. 255