On my second atempt to print with PLA I had a nozzle jam. Nothing was extruding from the nozzle even at 260°C with hand extrusion (hand pushed filament). So I had no other issue than disassembling the nozzle to figure out what happened...

Disassembling the nozzle is quiet simple. All you have to do is remove the top acrylic and MDF parts by unscrewing the 3 screws that hold them. Then you can easily remove the small aluminium tube which will give you access to a PTFE (Teflon) tube. Remove that PTFE tube by carefully pulling it out with the help of some pliers. Try to get it out straight without turning it as this could damage the nozzle insulating cement. Then remove all what you can find inside the nozzle that might have caused the jam.

Before assembling it all back, have a look at your PTFE tube. Mine has shrinked in diameter at the tip that is inside the nozzle. I can't push a 3mm diameter filament by hand thru it anymore. It means that I have to change it... After some research on the web I contacted Klaszlo from arcol.hu that kindly answered me that unfortunately he doesn't have such replacement tube anymore. So I simply drilled back the shrinked hole and reverted the PTFE tube on reassembling (upside-down).

I'm aware that this PTFE tube will cause me some more problems in the future. I also decided to print at lower temperatures than I usually do. Not only to prevent my PTFE tube to shrink too fast, but also because the print quality is better : less stringing and better at overhangs printing.

I think some more prevention should be applied.