Category: VWR

Replacement Parts:

LN SP29327 – Adjustment Knob Kit

Recommended Supplies:

1. Pair of gloves
2. Bottle of 70% IPA
3. Cotton Swabs
4. Flat-head screwdriver

Step 1:

Hold the VWR Ergonomic High-Performance pipette in one hand with the button facing towards you. With the other hand, pull the button away from the pipette body. Please note that the button has two parts. The blue lower has a hex hole that interacts with the operating rod and the top half snaps onto the top of the operating rod to secure both button parts in place.

Step 2:

Using a flat-head screwdriver, depress the tab of the bolt by pushing it towards the finger hook.

While holding down the bolt (black tab retaining the knob), slide the knob (black cylinder) towards the top of the pipette.

Note: As you remove the knob from the pipette body, be careful not to lose the bolt and spring. The bolt and spring are under a decent amount of spring tension, and it is very easy to lose them.

Step 3:

Remove the bolt & spring from the keyed hole in the pipette body.

Step 4:

Remove the locking ring by sliding it out the top of the pipette.

Using a cotton swab (soaked in 70% isopropyl alcohol) to clean the surfaces in the pipette body that interacts with the adjustment knob assembly.

Step 5:

Reinsert the locking ring. It is important to have it in the right orientation for a proper fit. The locking ring has a side with one fin on it. This side matches up with the channel on the counter side.

Note: The tab on the locking ring faces down when it is inserted into the channel on the top of the pipette. The locking ring should fully seat in the pipette body.

Step 6:

Insert the spring and bolt into the designated hole in the body. Make sure to line up the bolt in the correct orientation (tab toward the top) to provide the clearance to seat the knob.

Step 7:

Reinsert the knob (black cylinder), paying special attention to depressing the knob. After the knob is fully seated, the bolt will click into the channel on the top edge of the cylinder.

Note: The knob is keyed to the calibration knob, line up the four fins with the channels in the knob. See the fins on the calibration knob and the channels in the knob (black cylinder) that interact with one another.

Step 8:

Fit the blue half of the button on the hex-shaped part of the operating rod.

Reattach the upper half of the button onto the end of the operating rod. You should feel a tactile click when the button is properly attached.

Related Posts:
Preventative Maintenance: VWR Ergonomic High-Performance (EHP) Single Channel Pipette
How to Calibrate a VWR Ergonomic High Performance (EHP) Pipette
Pipette Parts – Life Span, Life Cycle, and Performance
Top 10 Crimes Committed Against Pipettes

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.

Recommended Supplies:

1. Pair of gloves
2. Bottle of 70% IPA
3. Box of Kim Wipes
4. VWR Piston 1.5g Grease: LN SP29019 1.5grams or LN SP29021 for 30g
5. 1-2 foam swabs
6. VWR EHP single channel replacement parts can be found here.

Note: These instructions are applicable for the volume sizes 2uL-1mL of the VWR EHP single channel pipette.

It’s recommended that a 4-5 analytical balance be used to check the accuracy and precision performance of the pipette after preventative maintenance, part replacement & reassembly, and 1 hour equilibration period is completed.

Disassembly and Preventive Maintenance Process:

Step 1:

Press and hold down the VWR EHP tip ejector button as you pull down and slide the tip ejector sleeve away from the pipette shaft. See Figure 1.0

NOTE: Figure 1.1 shows the tip ejector sleeve removed from the pipette. See replacement parts for a complete list of tip ejector sleeves, if needed.

Step 2:

Unscrew the shaft coupling nut slowly and away from the pipette body. Figure 1.2

NOTE: There is an internal spring that is under pressure and may pop open forcibly. Open slowly over a table in case internal parts pop out.

NOTE: Once the shaft coupling nut is unthreaded and lower shaft assembly is separated from the body, the following parts are exposed for PM purposes:

1. Pipette Body
2. Shaft Coupling Nut
3. Pipette Shaft
4. Piston Assembly
5. Tip Ejector Sleeve
   Figure 1.3

Step 3:

Remove the following components from the VWR EHP piston assembly as in Figure 1.4:

1. Piston
2. Piston Spring
3. Large Retainer
4. Small Spring/Retainer
5. Seal Spacing Tube
6. Seal
7. O-Ring

Step 4:

Clean and remove old lubricant/grease from piston with a Kim wipe. Figure 1.5. Take care to not scratch the piston. Turn/fold over the Kim wipe, so a fresh and unused portion comes in contact with the piston. See VWR EHP replacement parts for piston assemblies, if a replacement is needed. Look for rust, scratches, warped/bent, pit marks, visible chemical splash.

Step 5:

With a clean foam swab apply a light, but slightly visible coating of the 1.5g piston grease onto the piston. Figure 1.6

Note: Lubricating the piston from the piston tip to approximately 2/3 of the way up is more than sufficient. No need to lubricate the entire piston.

Step 6:

Inspect and replace the seal and o-ring. It’s recommended to replace both at the same time to allow them to wear in together. See VWR EHP replacement parts for seal
and o-ring part numbers. Look for cracks, wear and tear, chemical splash, shape, etc.

Re-assembly Instructions:

Step 7:

Install the following parts in order as shown in Figure 1.8.

1. Install piston spring (1) onto piston (6).
2. Install large retainer (2) onto piston spring (1), then onto piston (6).
3. Install seal spacing tube (3) onto retainers (2).
4. Lastly install new seal and o-ring onto piston assembly. O-ring should be installed last.

How Piston should look upon reassembly:

Step 8:

Place piston assembly back into the pipette shaft. Then screw the shaft coupling nut back onto the pipette body until snug. Figure 1.9

Step 9:

Reattach tip ejector sleeve to pipette body. Figure 2.0

Step 10:

Allow fully reassembled VWR EHP pipette to equilibrate at least 60 minutes before verifying accuracy and precision on a 4-5 place analytical balance.

Related Posts:

How to Calibrate a VWR Ergonomic High Performance (EHP) Pipette
Preventive Maintenance: VWR Ultra High-Performance (UHP) Single Channel Pipette
How to Calibrate a VWR Ultra High Performance (UHP) Single Channel Pipette

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 calibrate a UHP pipette:

WARNING:  Performing a calibration adjustment on any pipette should always be the last resort. Visual and performance confirmation that the internal seal, o-ring, piston assembly, lubricant (as applicable), shaft assembly, and other vital pipette parts that impact the accuracy and precision performance of the pipette must be in good/optimal working condition. Failure to recognize and replace worn parts could have an impact and shorten the life span of the pipette, possibly leading to costly repairs. Performing a calibration adjustment without confirmation of good pipette parts is a short-term solution at best.

Equipment Needed to Calibrate a UHP Pipette

1. VWR UHP Pipette and 4-5 place analytical balance
2. Calibration Tool: LN SP19674
3. Calibration Concealment Decal

Optional Equipment:

1. Latex gloves
2. Small-bladed tool for removal of the calibration concealment decal
3. Kim wipes and 70% IPA: Used for wiping the pipette externally after calibration adjustment is completed
   
   Printable Calibration Log
   Printable Calibration Stickers (for use with Avery 5960 labels)

Step 1:

Set the pipette volume display to the 10% volume (i.e., for a 1000uL pipette, set to 100uL, see figure 1).

Note: It’s strongly recommended to perform any calibration adjustment at the 10% volume. This is where most pipette manufacturers perform their calibration adjustments due to linearity and uniformity (i.e., accuracy and precision).

Performing a calibration adjustment at any other volume than 10% may have a greater impact and skew the volume aspirated and dispensed at different volumes.

Step 2: 

Remove the calibration concealment decal (#1) with a small-bladed tool. Lay aside for re-installment later. See figure 2.0

Important Note: Verify that the two calibration switch indentations (#3) beneath the word CAL on the pipette body is in the down position, as shown in figure 2.0. If found in the up position, push the indentations into the down position with the calibration tool (# 4, per figure 2.1) prior to executing step 3.

Step 3: 

Pull the blue colored volume lock (#2) from the locked position (down position, see figure 2.0) to the unlocked position (up position as shown in figure 2.1.)

Step 4: 

With the volume lock in the up position (unlocked), insert the calibration tool into the calibration switch indentations and move the indentations into the up unlocked position. See Figure 3.0

CAUTION:  At this point, the pipette calibration mechanism is now in the unlocked position and vulnerable to any adjustments of the volume lock.

Step 5:

To adjust/calibrate the UHP pipette, Rotate the volume lock until the displayed volume matches the mean volume that was aspirated and dispensed.

Step 6:

Push the volume lock in the down position and calibration switch indentations back to the down position.

Step 7:

Check your calibration adjustments on a 4-5 place gravimetric balance.  Repeat process until pipette is within acceptable tolerances for both accuracy and precision.

Step 8:

Reapply the calibration concealment decal to the pipette.

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.

VWR UHP Preventive Maintenance Recommended Supplies:

• VWR UHP Pipette Lubricant
  Pipette Supplies PN: LN SP29019 (1.5 grams)
  Pipette Supplies PN: LN SP29021 (30 grams)
• PM Parts: O-ring, seal, piston
• VWR Pipette Calibration Tool: LN SP19674
• VWR UHP Pipette
• Foam brush-lubricant application
• 4-5 place analytical balance
• Pipette Tips
• Di water or Distilled water

(All VWR UHP Single Channel Parts)

Optional UHP Preventive Maintenance Supplies:

• Kimwipes
• 70% IPA Alcohol
• Soft-Bristled Toothbrush

Step 1:

Carefully unscrew the liquid end assembly from the pipette body as shown in Figure 1.0.

Lay aside the pipette body for reassembly after preventive maintenance is completed.

Step 2: 

Carefully unscrew the liquid end coupling nut from the tip ejector sleeve as shown in Figure 2.0.

Note: In Figure 2.0, you start to see the shaft assembly being exposed.

Step 3:

Carefully unscrew the piston assembly cap from the shaft assembly, per Figure 3.0

CAUTION: Be careful when unscrewing the piston assembly cap as the internal piston spring and components are under tension and may pop out.

Step 4:

With the piston cap removed, the piston assembly and components are now visible for inspection, cleaning, preventive maintenance, and replacement as needed.

1. O-ring
2. Seal
3. Blow-out spring
4. Piston
5. Piston Retainer
6. Stroke Spring

Helpful Tip: Parts 1 through 6 comprise what is commonly referred to as the piston assembly.

Note: 

At this stage, carefully inspect parts 1 and 2. These are one of the most critical components of the entire pipette and should be inspected, cleaned, and/or replaced routinely.

With a Kimwipe or lint-free towel and 70% IPA, remove any lubricant, debris, or chemical splash from the piston assembly (# 1 – #6) and the inside/outside of the shaft (#7).

Step 5:

Replace the old o-ring and seal with new parts. (All VWR UHP Single Channel Parts)

1. Seals: replacement once every 12 months, based on usage
2. O-rings: replacement once every 12 -24 months, based on usage

Step 6A:

Once fully cleaned, apply a minute, but visible amount of piston lubricant (see page 1, PM Supplies Needed Section for part numbers) to a foam swab (DO NOT use cotton swabs as tiny stands of cotton may come off and mix with the lubricant).

Step 6B:

Carefully place a visibly light coat of lubricant onto the piston and retainer. Do not over apply the lubricant as accuracy and precision could be affected. See Figure 4.1.

Step 7:

Install the new seal onto the piston, followed by the o-ring. See Figure 4.2

Note: It is very important that the seal is installed first, followed by the o-ring. DO NOT mix orientation, as it may affect accuracy and precision.

Step 8: 

With a foam swab and 70% IPA, clean and swab the inside of the shaft to remove any debris, lubricant, or chemical splash that may have migrated inside of the shaft. Look for any visible wear, dullness, pit marks, or scratches on the shaft, ESPECIALLY in the area where the pipette tip seals to the shaft. Replace shaft as needed.

Pipette Reassembly After Completion of Preventive Maintenance

Step 9:

Place the piston assembly back inside the shaft. Carefully screw back on the piston assembly cap to secure the piston back inside the shaft as shown in Figure 4.3 above.

Step 10:  

Clean and allow the tip ejector sleeve to fully dry. Once cleaned and dried, carefully screw the tip ejector sleeve back onto the shaft assembly as shown in Figure 5.1

Step 11:

Carefully screw the tip ejector and shaft assemblies back onto the pipette body until snug. See Figure 6.0

Helpful Tips:  

Once the UHP pipette is fully reassembled after preventive maintenance:

1. Set the pipette volume to nominal (100%), install a pipette tip and aspirate Di water into the tip. Carefully withdraw the pipette and tip from the water and allow the water to remain in the tip for 15 seconds. REASON: to look for any visible leakage of water dripping from the tip. If there are No leaks, allow pipette to equilibrate. If there are visible leaks, recheck your work.

2. Allow the UHP pipette to equilibrate for at least 60 minutes upon completion of preventive maintenance. REASON: Pipette needs to equilibrate back to ambient conditions. Conditions that were caused by performing PM (heat of our hands, etc.) impact overall pipette performance.

3. After 60 minutes of equilibration, confirm the accuracy and precision of the pipette on a 4-5 place analytical balance. On some occasions, a calibration adjustment may need to be made only after rechecking your work and confirming the parts and PM actions are sound/good.

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

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 calibrate a VWR EHP:

ATTENTION: Performing a calibration adjustment on any pipette should always be the last option, never the first. Performing a calibration adjustment as the first option, may mask underlying pipette performance issues that could affect both the short and long term health of your pipette. This could lead to costly repairs and part(s) replacement, and possibly the need to replace the pipette itself.  Adjusting the pipette calibration should only occur if necessary and after the pipette sealing system (i.e.: piston, shaft, o-ring, lubricant, pipette tips) and other critical components are inspected to ensure good working condition. If not, replace part(s) as needed first.

Required Tools and Equipment:

• Calibration Tool part number: LN SP29334
• VWR EHP Pipette Tips or universal tips
• Di-Water (Non-Aerated)
• 4-5 Place Balance for Verifying Adjustments

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

Step 1:  

To calibrate a VWR EHP, unlock the volume lock by pushing down on the black lock assembly as per the picture.

Note: If you have a fixed volume pipette, the calibration wheel is located underneath the cap. Pull the cap outward to access the calibration wheel and skip to Step 4.

Step 2:

Set the pipette volume to the 10% volume (i.e., 20uL for a 200uL pipette, 100uL for a 1000uL pipette, etc) and relock.

Step 3:

Remove the plunger button from the pipette and lay aside. NOTE: the plunger button may come apart into two pieces, which is okay.

Step 4:

Insert the calibration tool onto the plunger rod.

Step 4A:

Align the prongs of the calibration tool with the notches on the pipette calibration screw.

Step 5:

Rotate the calibration tool no more than an1/8 of a turn in the:

• Counter-Clockwise Direction (+) to increase the volume aspirated and dispensed.
• Clockwise Direction (-) to decrease the volume aspirated and dispensed.

Step 6:

After each calibration adjustment that is performed, verify the volume aspirated and dispensed on a 4-5 place balance. Readjust the calibration as necessary.

Step 7:

Remove the calibration tool from the pipette, reattach the plunger button. Pipette is now ready for use.

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.