Troubleshooting - VWR Signature EHP Manual Del Usuario

VWR EHP-03-2008 13 9-04-08
• Holding the volume setting knob to protect it against
rotation, insert the calibration key into the cuts of the
calibration screw, (Fig. 4B)
• Turn the key clockwise to reduce the aspirated volume,
or counter-clockwise to increase the volume, (Fig. 4C).
One full turn of the calibration key changes the pipettor
aspiration volume by the amount given in the table
• Take out the key and fix the pipetting pushbutton,
(Fig. 4D). The pipetting pushbutton should be fixed in
opposite order.
Determine the average aspirated volume. The average
volume should be within the permissible range given in
the table.
If the volume exceeds the values stated, the recalibration
procedure should be repeated.
In case of pipetting the liquids with physical properties
considerably different from those of water, follow the
rules given in section 5.

9 - TROUBLESHOOTING

If you notice an improper pipette operation identify the
cause and eliminate the fault. To do this, follow the
instruction in the sequence provided. Replacement of
parts should be required only occasionally, and should
not occur under normal pipette use.
Droplets of liquid remain in the pipette tip.
• The tip is emptied too fast.
Decrease the speed of pressing the pipette pushbutton.
• The tip wettability has increased due to extensive use.
Replace the tip with a new one.
Droplets of air appear in the liquid aspirated into the tip.
• The pipette tip immersion is too shallow.
Immerse the tip deeper according to the instructions.
• The pipette tip is incorrectly pressed onto the pipette shaft.
Press the pipette firmly.
• The tip is damaged or worn out due to extensive use.
Replace the tip with a new one.
The pipette incorrectly aspirates the liquid or liquid
drops out from the tip.
• The pipette tip is incorrectly pressed onto the pipette shaft.
Press the pipette tip firmly.
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• The shaft nut is loose (Fig. 3F) in the models VWR VE2/V2
-VWR VE1000/V1000
Tighten the shaft nut.
• The sealing surface of the shaft is cracked or scored.
Remove the tip ejector. Unscrew the shaft nut,
inspect the shaft and the piston assembly. Replace
the damaged parts (see Section 12). When reasembling
the pipette, the nut should be hand tightened.
In the models VWR VE2/V2 - VWR VE20/V20, the damage
of the shaft may also cause a damage of the piston
assembly. Replace the damaged parts (see Section 12).
When reasembling the pipette, the nut should be
hand tightened.
To remove the tip ejector in models VWR VE5000 and
VWR VE10000, remove the ejector pushbutton (Fig. 3N)
and using a screwdriver unscrew the tip ejector by
turning the screwdriver counter-clockwise.
• Damage to the piston or seal due to prolonged use
with the aggressive liquids.
Disassemble the pipette as described above.
Replace the piston, seal and O-ring (see Section 12).
Rinse the inside of the shaft in distilled water and dry.
Lubricate the seal and O-ring with the lubricant, that
has been included with each pipette.
The replacement of the piston requires conducting
of the calibration procedure.
Note: The parts of VWR VE2/V2 and VWR VE10/V10
pipette should be lubricated evenly with a minimum
amount of lubricant.
• The pipette is reassemled improperly.
Disassemble the pipette and reassemble it,
observing the proper sequence of steps (Fig. 3).
• No lubricant on the sealing elements.
Remove the tip ejector. Unscrew the shaft nut,
remove the shaft, piston assembly, seal and O-ring.
Rinse the removed parts in distilled water and dry
thoroughly. Lightly lubricate the inside surfaces of
the seal and the O-ring with the included lubricant.
Reassemble the pipette in the reverse order.
• Contamination of the inside of the pipette caused by
extensive aspiration of chemically aggressive liquids or
because liquid got inside the pipette.
ENGLISH
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