Clear all

[Solved] Filament not loading  

New Member
Filament not loading

I made the mistake of letting a filament run out completely. When the extruder detected end of filament it started going through filament unload process, but there was no filament to pull out.

Anyway, now I am in a situation where I cannot load filament. If I manually heat nozzle to 260, and push in filament after opening idler door, filament flows out freely. But Load Filament process is no longer working.

I have been using PLA only.

What are my options?

Posted : 23/04/2021 7:57 am
Honorable Member
RE: Filament not loading

Letting the printer run out of filament is not a problem, that's the whole point of the filament sensor.

Prusa Knowledge Base | IR Filament Sensor Troubleshooting (MK2.5S, MK3S) (

Prusa Knowledge Base | IR Filament Sensor (MK2.5S, MK3S) (

Maybe have a look at these 2 documents, they are for troubleshooting filament sensor issues.

Also check Autoload Filament is switched on, and that the Filament sensor is switched on

Settings > Fil.Sensor = ON

Settings > Fil.Autload = ON


Tank you very much!...
Posted : 23/04/2021 8:10 am
Illustrious Member
RE: Filament not loading

I'd check for filament bits being trapped around the idler ball bearing in the sensor area - wedging the ball in so that the sensor state doesn't change as filament is pushed down the filament path.  You can check for this by monitoring the sensors in the menus (the troubleshooting guides should explain how to get to and use the sensor readouts).

Posted : 23/04/2021 8:15 am
New Member
Topic starter answered:
RE: Filament not loading

Thanks for the quick responses.

The problem, as it turned out, was a loose set-screw in the idler pulley. I tightened it, and stuff's flowing again..

Posted : 23/04/2021 8:31 am