Used Eppendorf Refrigerated Centrifuge, Pipette Tips, and Repeater: A Lab Manager's FAQ

I've been handling lab equipment purchases and service orders for eight years. I've personally made (and documented) 11 significant mistakes, totaling roughly $12,000 in wasted budget. Now I maintain our team's equipment checklist so nobody repeats them. When I first started, I assumed 'refurbished' meant 'like new, but cheaper.' It does not.

This FAQ answers the questions I get asked most, plus a few I wish someone had asked me before spending money.

Questions I've Learned to Ask

1. Is a used Eppendorf refrigerated centrifuge worth it?

It depends. A used Eppendorf 5810 R or 5424 R can be an excellent buy if the seller provides maintenance records, original rotor certification, and a trial period. It isn't a good fit if you need a factory warranty, GMP documentation, or new equipment traceability for an audit.

In my first year (2017), I made the classic mistake: I focused on price and brushed past the rotor log. The unit ran fine for about five months. Then the rotor failed the annual inspection. The replacement rotor cost more than the savings from buying used, and the delay hurt a project. I've never skipped rotor history since.

Take it from someone who learned the hard way: a used Eppendorf refrigerated centrifuge is only a bargain when you verify the rotor.

2. What should I check before buying a used Eppendorf refrigerated centrifuge?

Before I write a PO, I check these:

• Rotor model, serial number, and remaining service life.
• Refrigeration performance at 4°C, not just 'it is cold.'
• Lid interlock, imbalance switch, and alarm behavior.
• Service invoices: what was actually replaced or tested.
• Who will service it after the sale.

This may sound like overkill, but the people I've trained know not to say 'refurbished' without attaching a document. I said 'refurbished' once; the seller heard 'a box from eBay.' We were using the same word and meaning two different things. The communication failure cost us a week.

According to Eppendorf's rotor maintenance guidelines (eppendorf.com), rotor life is tied to the serial number and cycles. Get that information before you commit.

3. Eppendorf pipette tips compatibility chart: which tips actually work?

This is one of the most common searches, and the honest answer is that 'compatible' means more than 'fits.' Eppendorf's own epT.I.P.S. are qualified for Eppendorf pipettes. If you're looking for an Eppendorf pipette tips compatibility chart, start with Eppendorf's published pipette/tip list, then do the real test in your lab.

When I first started, I thought any tip from the same rack must be fine. Then a generic box of tips looked perfect on our Research Plus multichannel pipettes but leaked on the sixth channel. We discovered it during a QC plate, when one lane was consistently low. That mistake cost about $800 in repeats and the whole lab's schedule took a hit.

Now we keep a wall chart with the exact tip brands, catalog numbers, and which pipettes they've been verified on. I recommend you do the same. If you find a third-party tip that passes a gravimetric check, great. But don't assume it works just because it clicks.

4. How to use an Eppendorf Repeater pipette

This is one of those 'it's easy once you know' tools. The most common beginner error is treating it like a normal air-displacement pipette. It isn't. The Eppendorf Repeater uses a Combitip that is both the reservoir and the tip. Here is the basic workflow:

1. Attach a Combitip until it clicks.
2. Prime it by aspirating once and expelling the air, following the model's instructions.
3. Set the volume to the desired setting.
4. Dispense with a firm, even press.

In 2021, a new lab member used ours like a regular pipette and kept adding a fresh tip for every sample. He emptied a box of Combitips in minutes. That wasn't his fault; I hadn't explained the difference. The manual is clear: the Combitip itself is the syringe. You don't change it between samples unless you need to avoid contamination.

If you need the exact steps for your model, check Eppendorf's official manual on eppendorf.com. It will save you from the mistake I made: skipping the manual and assuming I knew.

5. Can a 73 multimeter test an inductive ring sensor?

This question is more niche, but it's exactly the kind of thing that shows up when you're troubleshooting a used centrifuge or a refurbished unit. The inductive ring sensor in some Eppendorf centrifuges tells the control board whether the rotor is seated or if the lid area is in a safe state. It's a proximity switch, not a complex speed encoder.

If you're electrically qualified, you can use a 73 multimeter (mine is an old Fluke 73) to do a basic check. With power off and the sensor disconnected, measure resistance across the sensor coil. An open or shorted reading tells you it's bad. If the sensor has a discrete output, you can bench power it and verify the output switches when you place a metal target near it.

But here's the limitation: a multimeter can't verify the sensor's air gap or its reliability at cold temperatures. I once saw a sensor that passed a bench test but failed when the centrifuge was at 4°C. The connector had moisture. The 73 multimeter said 'fine.' The centrifuge disagreed.

So use the 73 multimeter for continuity, but don't use it as the final word. When in doubt, replace the sensor with an Eppendorf spare part and get a service tech to do the dynamic test.

6. Do I need to calibrate Eppendorf pipettes and centrifuges regularly?

Yes. For pipettes, calibration is the only way to prove your volumes are correct. Eppendorf's calibration service is solid, but even if you use a local service, the key is traceability. We calibrate every 12 months and after any drop. For centrifuges, annual preventive maintenance matters more than people think. The rotor, lid seals, and sensor system all affect safety. If you bought a used Eppendorf refrigerated centrifuge, schedule a maintenance visit before you put it into critical work.

This is where I have to be honest: I recommend Eppendorf for most labs, but not for every lab. If you're a startup on a tight budget, a well-documented used Eppendorf plus a calibration report is a better buy than a cheap new centrifuge from an unknown brand. If you need urgent repairs and don't have a service contract, maybe a new unit with local support is better for you. No single answer works for everyone.