Another fan mystery

We discussed in the thread, viewtopic.php?f=58&t=15344 , what the little 25 mm fan on the print head does and according to an official answer from VEL it is supposed to cool down the PEEK.
I see no reason to doubt this even though the angel and position of it points to other places.

Now here is the mystery of the day; When you load/unload filament it goes constantly at full speed but when you heat the printer up for an actual print it does not move. Whats that all about ??

Hello monza64!

Thats no mystery!
When you are loading/ unloading filament the fan speed settings are controlled by marlin firmware (basic setting for fan 165 (max = 255)) and if you are printing the fan speed settings are controlled by g-code. Value 165 is much to high in my opinion if you want to heat up fast. Both fans are connected to the same output and are blowing towards the heater blocks also.

The marlin setting you can change in the settings menu (LCD screen) and the g-code settings are changeble in the filament settings tab in Cura engine.

See also:
viewtopic.php?f=58&t=15344

To me its still a mystery why there is a difference in the behavior. I understand its differently coded, but why ?

The thread you refere to was also mine and as you can see from the picture I made changes in the fan position. It works fine, only problem was that it was cooling the heated end up so it was impossible to reach ABS temps so I had to make a wind screen.