The print fan is the fan blowing on the printed object, right below the nozzle. Depending on the material and where you are in the print it might not always spin at full speed or at all. There is also an error in the firmware connected to the fan not spinning. If you did not receive any error but the fan does not spin, you will probably find the solution in this article.
|MK2/S, MK2.5/S, MK3/S/+ print fan (green circle)
|MINI/MINI+ print fan (blue arrows)
The print fan is never used during the first layer of any material. It will start from layers 2-4, depending on the material profile selected. For example with PLA, the print fan is spinning at 100% all the time until the print finishes. For ASA and ABS, the fan is turned off completely for the first 4 layers then will only spin at 15-20%, with a slight increase when printing Bridges. At very low speeds the print fan can be almost inaudible.
|PLA settings - Fan always 100%
|ASA settings - Fan only 20% at fewer layers.
Make sure that the fan is:
If the fan still 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/S/+) power source. If the fan spins up with an external power source, check the electronics for your printer and its fuses: