Hotend fan is not spinning

Updated 1 day ago ​by Tomáš Chvalina

Before we start checking your Hotend fan, power down and unplug your USB cable if connected. Open the electronics covering and examine the MK2/MK2S miniRAMBo electronics wiring or MK3 EINSY miniRAMBo electronics wiring.

Make sure that the fan is:

  1. Plugged into the right connector.
  2. Plugged in with the proper connector orientation.
  3. Plugged in completely and making good electrical contact.

You can easily test the nozzle Hotend fan function from the LCD menu Preheat - PLA. When the Hotend temperature reaches the 50°C, the fan should immediately spin up.

If the fan doesn't spin up, you can unplug it from the electronics board and test it with the 12V DC (MK2/S) or 5V DC (MK3) power source. If the fan spins up to an external power source, check all the electronics wiring in MK2/MK2S Electronics Wiring or MK3 EINSY miniRAMBo electronics wiring and potentially fuses in Blown Fuse (miniRAMBO).

When the Hotend fan should actually spin

Hotend cooling fan cools down the top part of the Hotend (heatsink) from the heat which is transferred from the heater block. It always starts up when Hotend temperature reading reaches 50°C and spins for the whole duration of the print! If the fan is not functioning, you can expect the nozzle to jam after the first few layers.

Always make sure that the fan is pushing the air through and around the heatsink and not out.
Propper orientation of the hotend fan can be checked at the photo down below. 

Do not hesitate to contact us at if you have any further questions.

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