Metrohm 700 Dosino - Manual (Page 37)

3.4 Troubleshooting / Problems
700 Dosino, Instructions for Use
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3.4 Troubleshooting / Problems
3.4.1 Dosino buret
Dosing drive cannot be mounted on the dosing unit.
Possible causes:
• The carrier of the drive is in the wrong position.
⇒ Switch the control instrument off and then on again. If the car-
rier does not automatically rotate to the starting position
switch it off again and rotate the carrier manually to the cor-
rect position. Pay attention to the marking ribs: rib on rib. See
page 9.
• The centering tube is wrongly positioned.
⇒ Rotate the centering tube of the dosing unit into the correct
position by hand. Pay attention to the marking ribs: rib on rib.
See page 9.
• The dosing piston is in the wrong position. The piston peg
must be flush with the housing.
⇒ Use the piston pliers to pull out the piston to the stop (take
care with the 2mL buret) and press the inverted dosing unit
against a flat surface. See page 10.
• The push rod of the drive is wrongly positioned.
⇒ Place the drive on the empty housing of a dosing unit and
press <FILL> or <EXCH>.
Dosing drive cannot be removed from the dosing unit.
Possible causes:
• Piston and/or 4-way valve are not in the 'Exchange' posi-
tion.
⇒ Carry out 'EXCH' or 'FILL' function on the control instrument.
Check cable connections to control instrument.
⇒ Switch control instrument off and then on again.
⇒ Lock the drive on the dosing unit, i.e. turn it to the left until it
reaches the stop.
• If the dosing unit still cannot be removed after the 'EXCH'
or 'FILL' function has been carried out then either the pis-
ton or the 4-way valve is blocked or even damaged. Proce-
dure:
1. Switch off control instrument.
2. Press the white knob of the dosing unit and remove the dis-
tributor. Place Dosino buret in an inverted position.
3. Switch on the control instrument and trigger EXCH or FILL. If
you can clearly hear the valve rotating the Dosino buret can
be replaced on the distributor.