Prusa Mk3S MMU2 E3d V6 Hot-end Nozzle Changing Procedure

Remove Nozzle

Unload Filament

  • Unload Filament if necessary.

Move Z Axis Up

  • Settings -> Move axis -> Move Z -> [about 190].

Remove Silicone Sock

  • Remove any Silicone Sock. This may be hot and can burn you!

Preheat Nozzle to 285C

  • Settings -> Temperature -> Nozzle: 285 C.
  • Do not touch Block or Nozzle! These are very hot and will burn you!

Remove Nozzle

  • When the nozzle temperature is 285 C.
  • Hold the heater Block steady with a 16 mm spanner, or wrench.
    • Do not let the spanner touch the heater, thermistor, or wires. Avoid damaging them.
  • Do not allow the Block to move (best), or only twist the Block a very small amount.
    • If you allow the Block to move (twist) then the Block may creep on the heat break thread. The filament may leak when you print.
  • Use a 7 mm socket with extension to remove the Nozzle using only hand force.
  • Clean Nozzles during and after changing!
    • The interface between the Nozzle and the heat break must be flat and clean! While the nozzle is still hot use a wire brush to clean nozzle thread and heat break interface.

Replace Nozzle

Replace Nozzle

  • Check and if necessary clean the new nozzle.
    • The interface between the Nozzle and the heat break must be flat and clean! If necessary lightly file or fine grit-paper the interface clean and flat.
  • Insert and tighten the new Nozzle full finger tight using the socket and extension.
    • Do not use a socket wrench, or driver; do not over-tighten the Nozzle!
  • After tightening the Nozzle: check that there is still space between the top of the Nozzle and the bottom of the heater Block.

Lower Nozzle Temperature

  • Set the Nozzle Temperature lower as required.

Check and Set Live-Z

  • Settings -> Live adjust Z ->

Check and Set Nozzle Size in Hardware Settings

  • Settings -> HW Setup -> Nozzle d.

Replace silicone sock

  • Replace any Silicone Sock: take care to not damage the heater or thermistor wires.
  • Do not touch the Block or Nozzle! These are likely still very hot and will burn you.

Load Filament

  • Load Filament as necessary.



  • 16 mm Spanner or Wrench.
  • 7 mm Socket.
  • Socket extension (approx. 70 mm). The socket will get hot and the extension helps you to avoid burning yourself.

Filament Leak!

  • Stop printing!!
  • Do not allow the leak to build up burnt plastic residue!
  • Check that you fitted the nozzle correctly. There must be a (small) gap between the top of the Nozzle and the bottom of the Block.
  • If the nozzle is flush against the bottom of the block, then you could disassemble and rebuild the hot-end to stop the leak.

Assembling Nozzle

  • Use 1/2 turn for nozzle gap from the block when tightening against the heat break; not 1/4 turn. This is based on my experience and may be different from E3d advice.

Disassemble Hot End

  • Disconnect the heater and thermistor wires from the board and wiring loom before removing the hot end. I try and leave some slack in the wiring loom to avoid doing this.
  • Do not bend or put strain on the wires from the heater block!
  • Remove, clean, reassemble, and refit the hot end. See online advice for how to do this.
  • Re-calibrate the printer before printing again.

E3d V6 Nozzle Series - Marks for Nozzle Size

  • 0.15 mm: 2 on 1 face.
  • 0.25 mm: 0.
  • 0.30mm: 1.
  • 0.35 mm: 2.
  • 0.40 mm: 3.
  • 0.50 mm: 6.
  • 0.60 mm: 4.
  • 0.80 mm: 5.