Replace the radial fans of the Ultimaker 3

The fans at the side of the print head spin during printing. This ensures that the layer of filament is properly cooled down before the next layer is put on. Most materials require this extra cooling to retain optimal print quality.

If the fans are not spinning, they need to be replaced. The following steps describe how to correctly replace the model cooling fans.

Caution: Make sure the filament is removed, the Ultimaker is turned off and power supply disconnected before you start the replacement. Ensure print cores are cooled to avoid burning yourself.

Parts required:

  • 1 or 2x 2135 Radial fan

Tools required:

  • 2.0 Hex screwdriver


  • 15 minutes


1. Loosen the side fan bracket

  • Place the print head in the middle of the printer for easier access.
  • Use the hex screwdriver to remove the four screws that hold the side fan bracket.

2. Move the fan bracket down

  • Slightly open the front fan bracket.
  • Move the front and side fan bracket assemblies down to create some room.

Ultimaker3_Loosen-side-fan-bracket.jpg Ultimaker3_Move-fan-bracket-down.jpg

3. Disconnect the fans

  • Turn the Ultimaker 3 around.
  • The radial fans are connected to the left and right connectors at the back of the print head.
  • Carefully remove the fan plugs from the connectors.

4. Remove the fans from the bracket

  • Take the left side fan and pull it out of the bracket, it is not screwed into place.
  • Repeat for the right side fan.

Ultimaker3_Disconnect-side-fans.jpg Ultimaker3_Remove-fans-from-bracket.jpg


1. Prepare the new fans

  • Take the right side fan and hold it in the correct orientation; the open side facing down and the fan towards the left as it would be placed in the print head.
  • Loop the wires behind the fan, with the plug towards the back and approximately 3 cm of wire sticking out. This ensures good cable management.
  • Repeat for the left side fan, but with the fan towards the right.

2. Place the fans in the bracket

  • Slide the right side fan into the fan bracket.
  • Make sure that the fan wires come out from behind the fan at the back.
  • Repeat for the left side fan.

Ultimaker3_Loop-fan-wire.jpg Ultimaker3_Place-new-side-fan.jpg

3. Connect the fans

  • Take the plug from the left side fan (as seen from the front) and connect it to the connector on the right (as seen from the back).
  • Take the plug from the right side fan (as seen from the front) and connect it to the connector on the right (as seen from the back). 

4. Attach the side fan bracket

  • Align the side fan bracket with the header bracket.
  • Secure the fan bracket with the four screws.

5. Close the front fan bracket

  • Push the front fan bracket upwards to close it.
  • Check if it moves smoothly. If it does not, you may need to relocate some wires or fix the connection to the side fan bracket.

Ultimaker3_Connect-side-fans.jpg Ultimaker3_Attach-side-fan-bracket.jpg


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