Category: Gilson

How to Remove and Install a New Counter Assembly for Gilson Pipetman with the Counter Disassembly/Assembly Tool

In this post:
Counter Removal Tool: PS 10002
Gilson Counter Assemblies
Pipetman Classic Replacement Parts: Single Channel

NOTE: These instructions are not recommended for the Pipetman L. You can find Pipetman L Counter Assembly instructions here.

Disassembly

Step 1:

Press and hold down the white colored tip ejector button. This will slightly lower the stainless-steel tip ejector arm and make it easier to remove. With a little force, carefully pull down on the tip ejector arm to detach and remove it from the pipette body. Lay aside for reassembly later.

Step 2:

Carefully unscrew the shaft coupling nut from the pipette body.  

CAUTION:  When the shaft coupling nut is removed from the pipette body, the internal piston assembly might forcefully pop out from inside the white colored shaft. Take great care so the internal piston assembly and components do not pop and fly out of the shaft, or you may be forced to locate and or replace the seal, O-ring, seal retainer, stroke spring, blowout spring, or piston, if lost. Internal piston assembly components may vary slightly based on pipette nominal volume size. Lay aside for later.

Step 3:

Turn the to adjust the pipette plunger button and volume display to nominal volume (i.e., 100% of the pipette volume)  

Step 3A:

Then gently rotate the volume increasingly past nominal volume until the plunger button and volume display will not rotate further. STOP and do not force the volume turning further. Usually this occurs when the friction ring contacts the top portion of the pipette body.  

Step 3B:

Remove the plunger button from the pipette by pulling upward and away from the plunger rod. Lay aside for later.

Step 4:

Insert bent nose pliers into the two outer most holes on the black colored micro bolt and continue to rotate the micro bolt in an increasing manner until it can be removed and pulled out from the pipette body. Lay aside for reassembly later.

NOTE: the bent nose pliers will provide the extra torque needed to allow the micro bolt and friction ring to be removed from the pipette body.

COMMENT: If desired, you may cut off the plastic or rubber friction ring from the micro bolt with a razor blade prior to Step 3A. This means you will need to replace the friction ring with a new one, prior to reassembly. If the friction ring is not cracked or brittle, replacement is usually not needed.

Photo Comments (below): The micro bolt was already removed from the pipette body to show the outer most holes easier for viewing purposes.

Counter Removal Tool Illustration (PS 10002): Shown to identify each end for intended use during removal and installation

Step 5:

Insert the slightly thinner and contoured end of the counter removal tool into the pipette body opening.

CAUTION: if the counter removal tool does not insert easily into the body opening and feels like it is being forced into the body, stop! Please do not force the tool into the body or it may get stuck, damage the pipette body, and require excessive force to remove the tool. Based on the age of the pipette, there is a possibility that the body opening may have shrunk slightly due to properties of the materials, environmental, age of the instrument, etc.

Step 6:

With the thinner contoured end fully inserted into the pipette body opening, gently tap or bang the end of the counter removal tool vertically onto a hard surface such as a table or bench top 2-3 times to unseat the counter assembly from the pipette body. This should be done vertically as shown.

Step 7:

Remove the counter assembly tool from the pipette body and lay aside. Then, lift and remove the counter assembly out of the top of the pipette body.

New Counter Assembly, Installation, and Pipette Reassembly

Step 8 REASSEMBLY:  

Carefully align and gently insert the new counter assembly into the top of the pipette body.

Step 8A:

Insert the thicker/flush end of the counter assembly tool on top of the new counter assembly and gently push the new counter assembly until it is seated properly and fully into the pipette body. Once the counter assembly is properly seated, remove the counter assembly tool.

Step 9:

Refer to Appendix 1 and obtain the proper counter assembly digits needed for insertion of the micro bolt assembly back into the pipette body based on the nominal size of the pipette (i.e., 200uL, 1000uL, etc.). Loosely insert the micro bolt into the counter assembly and gently rotate until the desired counter assembly digits appear in the volume display window.

IMPORTANT: DO NOT ALLOW the micro bolt to seat into the pipette body until the desired digits are visible in the volume display window. This can be achieved by rotating the micro bolt and lifting it back out of the pipette and re-inserting it until the desired volume digits are visible in the volume display window.

Example: If the desired digits are 134 for a 1000uL pipette, loosely insert the micro bolt, rotate the micro bolt without it catching in the body, and remove/repeat until the micro bolt displays 134 in the volume display window.

Step 10:

Align the micro bolt assembly with the white colored notched tab on the counter assembly. Once aligned, insert and push the micro bolt into the body fully until it stops/seated.

Step 11:

Insert the bent nosed pliers into the two outer most holes on the micro-bolt.

Step 11A:

After insertion, press down and maintain force while turning the bent nosed pliers to seat the counter assembly fully back into the pipette body. Provide sufficient torque to allow the friction ring to seat back in place.

Step 11B:

When rotating the bent nosed pliers, the volume display digits will decrease as the micro bolt is seated back into place. Continue until the friction ring is below the top portion of the pipette body and the micro bolt can be rotated by hand and no longer with the pliers.

Step 11C:

Wind the pipette to the 10% volume.

Step 12:

Insert the piston assembly back into the shaft and place the coupling nut back on the shaft. Fully screw the shaft coupling nut back onto the pipette body.

Step 13:

Press down on the tip ejector button and reattach the tip ejector arm to the pipette body.

Step 14:

Verify the desired accuracy and precision of the pipette is obtained on an appropriate balance. Calibration adjustments may be needed.

Appendix 1: Counter Assembly Alignment Digit Settings

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

This Gilson Pipette Legend aims to clarify the nomenclature of Gilson pipette codes and shorthand. Most codes are a mixture of a prefix letter, the max volume in microliters, and occasionally a suffix letter.

Gilson Pipette Full Name	Gilson Code (Part# Prefix/Suffix)	Example of SC 1000μl or  MC 1200μl, etc
Pipetman Classic Single Channel	P	P1000
Pipetman Classic Fixed Vol Single Channel	F	F1000
Pipetman Concept Multichannel	C	C300
Pipetman G Single Channel	P_G	P1000G
Pipetman L Single Channel	P_L	P1000L
Pipetman L Fixed Vol Single Channel	F_L	F1000L
Pipetman L Multichannel	P(8 or 12)x(Vol)L	P8x300L or P12x300L
Pipetman M Single Channel	P_M	P1200M
Pipetman M Multichannel	P(8 or 12)x(Vol)M	P8x300M or P12x300M
Pipetman Neo Single Channel	P_N	P1000N
Pipetman Neo Multichannel	P(8 or 12)x(Vol)N	P8x200N or P12x200N
Pipetman P Single Channel	P or F	P1000, F1000
Pipetman Ultra Single Channel	U	U1000
Pipetman Ultra Multichannel	U8/U12-	U8-300, U12-300
Microman Positive Displacement	M	M1000
Microman E Positive Displacement	M_E	M1000E
Distriman Repetitive Dispenser D-Man	D
Autorep Repeating Pipet	AR

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

Lock/Unlock Assembly Parts

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

Styles of Gilson Pipette Tip Ejectors:

Use this chart to confirm which style of tip ejectors are compatible with your Gilson pipettes. The following chart can be used for Pipetman Classic, G, L, M, and Neo(N) pipettes.

Shop all Gilson Pipette parts (including tip ejectors) here.

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

Instructions to use the Pipetman L Calibration Tool. Link to product page: 28888

This tool is for increasing or decreasing the pick-up volume during the calibration process.  Review and follow the Gilson publication, Verification Procedure for Accuracy and Precision.  Contact Us for a copy.

Be sure that the sealing system of the pipette (piston, tip holder, seal and o-ring) is functioning properly.  The pipette liquid end must be leak-free.  If it is not, calibration will not be effective. 

Printable Calibration Log
Printable Calibration Stickers (for use with Avery 5960 labels)

CALIBRATION INSTRUCTIONS:

Step 1:

Set the Pipetman L pipette to its minimum test volume according to the user manual (usually 10% of the nominal volume). 

Step 2:

Pre-rinse the tip. Dispense and weigh four individual samples. Determine the mean weight of the samples in micro-liters (µl). If the mean is not within accuracy limits, continue with the calibration.

Step 3:

Remove the plunger button from the pipette by pulling it straight up.  Push the volume control disc down to the lock position.

Step 4:

Insert the two prongs, C, of the Pipetman L calibration tool into the two slots of the center access button of the volume control disc. Rotate the tool counterclockwise about 15 degrees and pull out. The center access button will come out loaded on to the two prongs. Hold the button in one hand and rotate the tool in clockwise direction to disengage and unload the button from the tool.

Step 5:

Holding on to the large knob A and letting the outer barrel with the knob B slip down on its own weight, slide the tool over the plunger rod and let it go inside the pipette body as far as it can on its own weight.

Step 6:

While pressing down VERY slightly, rotate the knob B.  The two prongs of the knob B will engage with the square part of the calibration mechanism of the pipette in less than 45 degree of rotation.  

Step 7:

Rotate the large knob A without pressing down.  The groove C of the inner rod will fit over the inner member of the calibration mechanism.

Step 8:

To increase the pick-up volume, hold the knurled knob B firmly without letting it move and rotate the large knob A in counter clock direction; to decrease the pick-up volume rotate the knob A in clockwise direction.  Rotate ONLY about half turn at a time and re-check the mean weight as done in step 2.

NOTE:  You do not need to put back the center access button into the volume control disc at this stage, just replace the plunger button making sure that the flats of the plunger button align with the flats of the plunger rod.

Step 9:

Check the pipette at the 10% volume as done in step 2.  If the pipette is within the specification, continue with the next step.  If not, return to step 2.

Step 10:

Set the pipette to its maximum volume and perform the calibration test.  If the instrument is within accuracy limits, it has been calibrated successfully.  If it is outside the accuracy limits, return to step 2 and repeat the process.

Step 11:

Remove the plunger button again.  Load the center access button on to the two prongs C of the Pipetman L calibration tool, insert the button in its place and turn the tool about 15 degrees clockwise. The button will lock in the volume control disc.  Pull out the tool and install the plunger button on the plunger rod.

“Pipetman” is a registered trademark of Gilson, S.A.S.

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

Gilson Pipetman Eras:

Old-Style Pipetman: Introduced in July 1979. Serial numbers range from H-79xxxxx through N-85xxxxx. Two-piece piston assemblies introduced June 1982 (G-82xxxxx). Have three (3) upper silver colored calibration screws, and three (3) lower brass colored screws. The actual calibration mechanism is silver colored not upgraded to a black calibration screw as with the next Pipette era below.

All of the Gilson Pipetman eras have the same black colored, 6-hole calibration screw as shown below.

New-Style Pipetman: Introduced in January 1986 featuring a sturdier and new serial 6-hole calibration mechanism numbers CxxxxxA through JxxxxxA.

Modified Pipetman: Introduced in February 1991 featuring a new long-life friction ring. Serial numbers are JxxxxxB through NxxxxxE.

Plunger-Adjustable Pipetman: Introduced in December 1995 featuring easier adjustment by using the volume adjustment knob or by turning the plunger button. Serial numbers range from NxxxxxE and higher.

See the chart below for Gilson Pipetman year classifications.

Related Posts:

Styles of Gilson Pipette Tip Ejectors

Trouble Shooting Gilson Pipetman Calibration Concerns

Gilson Pipetman Counter Assembly Realignment

Pipetman Calibration Wrench, Item # 27777

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

Pipetman Calibration Troubleshooting:

Printable Calibration Log
Printable Calibration Stickers (for use with Avery 5960 labels)

Before any Pipetman calibration adjustments are made, the seal, o-ring, shaft, piston, and pipette tip performance needs to be confirmed as being good and fully functional. These five (5) components account for 95% of all pipette performance issues with accuracy and precision (percentages below). Calibration adjustments are always the last resort after determining that the following parts are in good condition and functioning well:

• Seal and O-Ring 60%
• Piston 20%
• Shaft and Tips 10%
• Pipette Handle/Body 5%

Troubleshooting Pipetman calibration adjustments after confirming that the 5 Parts above are fully functioning:

• For pipettes that have three (3) silver calibration screws on the upper side portion of the volume adjustment knob and that are within the serial number sequence of H-79xxxxx – N-85xxxxx: Loosen the two-piece piston assemblies (introduced June 1982 [G-82xxxxx]) with a 2mm Allen wrench. Do not loosen the three (3) bottom brass colored screws. The upper three silver screws must be loosened before calibration is permissible.
  • If the upper, silver screws will not loosen due to being stripped, try a 3mm Allen wrench or a special drill bit that removes stripped or damaged screws.
  • Use a cordless drill on slowest speed setting and replace the three silver calibration screws.

• For pipettes that have a black, plastic, 6-hole calibration screw that won’t turn:
  • This could be due to:
    • The calibration screw is already adjusted to its maximum allowable range.
    • The coefficient of expansion and contraction of the plastic parts in changing environmental conditions and over time. Expansion and contraction of the plastic has a subtle impact in cold/hot seasons. 
    • Black calibration screw threads could be stripped or cross-threaded.
  • Gently clean and scrub the top of the calibration screw with IPA and a soft-bristled toothbrush. This is a difficult task, requires skill, and has a low success rate.
  • If the calibration screw won’t adjust after the 1st attempt, gently hold the black volume adjustment knob and friction ring with pliers (see tip below). Simultaneously, attempt to adjust the calibration with the calibration tool in the other hand. The extra leverage of the pliers holding the volume adjustment knob in place may provide the necessary torque when using the calibration tool to adjust.

PROFESSIONAL TIP:

Use rubber grips for the end of your pliers or wrench. The rubber helps to prevent damage to the friction ring and micro bolt. These can be purchased at any local hardware store or online.

You can also buy plastic shrink tubing, cut it to the desired size, and heat/shrink it in place it over the plier nibs.  This is the cheaper option; however, the tubing only lasts 2-3 months before it needs to be cut off and replaced.

Reminder: Adjusting the calibration should always be a last resort after the seal, o-ring, shaft, piston, and tips have been deemed fully functioning. 

Overall, if the calibration screws cannot be adjusted, we recommend sending the pipettes to a calibration service provider. The pipette may require replacement of the calibration screw and/or the volume adjustment knob.

Pipetman Calibration Tools/Instructions:

Pipetman Calibration Wrench, Item # 27777
Gilson Pipetman L Calibration Tool, Item # 28888

Related Posts:

Pipette Parts – Life Span, Life Cycle, and Performance
Counter Assembly Instructions for Gilson Pipetman / Rainin Classic
Styles of Gilson Pipette Tip Ejectors
Differentiating Between Different Gilson Pipetman Eras
Gilson Pipetman Teflon vs. Polyethylene Seals

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.