Clogging filament

Some types of filament is clogging in the E3D… head after some time, while it works normal with the original print head. The filament feels somewhat weeker (it will not break when stretched for some time). Has somebody a solution/ reason for this problem?

Good cooling of the heatsink is a must.
I use a 30 mm fan at 15V.
It keeps the heatsink at 40 deg Celsius, when the extruder is at 210 deg

My preheat options all heat the bed first, then the nozzle, and I think this is the right way to go… As you yourself note, having filament sitting at temp for 10 minutes in the nozzle, is not a good thing, its very likely that it will get burned and maybe harden up… I would look into how you can change the heating order… Probably you can for a print, edit it directly in the G-code by just switching a few lines. with the preheat options, I’m not sure, but it must be configurable in firmware.