Hoefer Single Channel Variable Pipette - Manual (Page 7)

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7. MAINTENANCE
Use 70% ethanol and a soft cloth or lint free tissue to wipe the external pipette surfaces
clean.
To clean in the interior of the pipette:
1. Hold down the tip ejector.
2. Place the pronged end of the wrench between the tip ejector and the tip ejector
collar to release the locking mechanism.
3. Carefully release the tip ejector and remove the collar.
4. Using the wrench, turn the tip cone counter clockwise to remove the cone.
5. Wipe the piston, O-ring and the tip cone with 70% ethanol. Note: Pipettes with
volumes of 10 µl or less have a fixed O-ring and cannot be accessed.
6. Grease the piston with a light coating of silicone.
7. Reassemble the pipette and then depress the thumb button several times to
lubricate the piston to make sure it does not bind.
8. Check calibration.
8. TROUBLESHOOTING GUIDE
Problem Possible Cause Solution
Tip incompatibility Try a different brand of tip Liquid left inside the tip
Plastic tip not uniform Attach a new tip
Tip incorrectly attached Reattach tip
Tip cone fouled Clean tip cone
Pipette has material inside
cone Clean and grease O-ring
and piston; clean tip cone
O-ring not positioned
correctly or damaged Replace O-ring
Leakage or pipette volume
too small
Calibration incorrect Recalibrate pipette
Piston damage Clean and grease O-ring
and piston; clean tip cone
Solvent contamination Clean and grease O-ring
and piston; clean tip cone
Push button jammed or
off center
Calibration incorrect Recalibrate pipette
Pipette not aspirating Material blocking cone tip Clean and grease O-ring
and piston; clean tip cone
Tip ejector jammed Ejector collar has debris Clean tip cone and ejector
collar