Check for debris in the Ultimaker S5's front fan of the print head

The front fan cools the print cores during a print. This helps to prevent the heat from the nozzle from traveling too far upwards.

The fan takes in air from the front of the print head and directs it towards the print cores. Sometimes the airflow causes thin strands of filament to be sucked into the fan during a print. If strands accumulate in the fan, they can decrease the effective cooling and eventually obstruct the fan and prevent it from spinning. Especially high-temperature materials, such as CPE+, PC, and ABS are prone to this.

If the front fan does not spin during printing, this can quickly lead to extrusion problems and obstructions in the print core.

To check the front fan, first gently open the front fan bracket. Blow into the front fan to see if it spins smoothly. If it does not move at all or stops spinning abruptly, carefully clear any obstructions from the front fan with some tweezers.

Caution: Make sure that the print cores are completely cooled and the printer is turned off before performing this check.

Tip: Some filament debris can also be visible from the outside of the print head. Make sure to remove this too.

After removing all visible filament debris from the fan, check if it spins. Via the menu, raise the temperature of one of the print cores. The front fan will be activated if one of the print cores reaches a temperature of 40ºC or higher. If the fan does not spin, it should be replaced. Please reach out to support or contact your local reseller for a replacement.


Note: This only affects the front fan and not the side fans of the print head. The radial side fans take in air from the top and are much less likely to get blocked. The side fans will only spin during printing to cool the model.

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