SeeMeCNC Rostock MAX v2 Assembly Manual page 251

The PEEK fan shroud is "virtually" linked to the hot end power. You should be able to see the
fan running as soon as you hit the Heat Extruder button in Repetier-Host. Do that now to make sure
the fan operates. When you run a print job, the PEEK fan will continue to run even after power has
been removed from the hot end. It will continue to run until the hot end temperature falls below 50C.
After you've got the PEEK fan installed, please re-run the auto-tune PID routine for the hot-end.
The running PEEK fan will have changed the heating profile and the PID variables need to be updated
in order to account for this change.
Rostock MAX v2 Assembly Guide
Fig. 23-21: Done!
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