Why am I feeling resistance when filling my cartridge with insulin? (t:slim X2 insulin pump)

When filling the cartridge with insulin, it is normal to feel some back pressure as you slowly press on the plunger. The needle tip is not intended to go all the way in, so do not force it. If the pressure is so great that you are unable to dispense the insulin into the cartridge, proceed to the troubleshooting steps below. 


Troubleshooting Steps: 

  1. Ensure you are not reusing the cartridge, syringe, or needle. 
  2. Remove the needle tip from the insulin fill port, then depress the syringe plunger. 
    1. If insulin comes out of the needle: attempt to fill the cartridge again. 
    2. If insulin does not come out of the needle, continue. mceclip1.png
  3. Remove the needle tip and secure a new needle tip to the syringe that is already filled with insulin, then attempt to fill the cartridge again. 
  4. If you are still unable to fill the cartridge with the second needle, discard the existing cartridge, and fill a new cartridge. 


To help avoid this in the future, make sure you are using proper load technique. If this issue is persistent, please contact Customer Technical Support. 



Load Sequence Tips (t:slim X2 insulin pump): 

  • Do not re-use or re-fill cartridges. 
  • Use the syringe that came with your cartridges. 
  • Use room-temperature insulin. 
  • Ensure there are no visible cracks in the cartridge. 
  • Ensure that there are no visible air bubbles in the syringe.  
  • We recommend filling the syringe with a minimum of 120 units. 
  • Only used approved insulins 
  • Ensure you insert the needle in the center of the white cartridge fill port. 
  • Do not overfill cartridges. The base of the syringe’s plunger should not pass the 3mL line. 


  • Ensure you remove the residual air from the cartridge before filling. 



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