On long prints heat can travel up the nozzle through the heat break, cause the filament to expand an jam at any contraction lower down. Pointing a fan above the heat break helps.
You can tell if this is your problem by pulling the filament all the way out after a jam and visually inspecting for swelling of the filament.
You can tell if this is your problem by pulling the filament all the way out after a jam and visually inspecting for swelling of the filament.
