On my stock Creality Ender-3 the PTFE bowen tube melts and starts to burn when it reaches 260 C that the printer allows out of the box, this commit attempts to decrease the max temperature by changing HEADER_X_MAXTEMP in Marlin to decrease the max safe temperature to 240 to avoid this fire hazard.
This issue can be reproduced by using 260C hotend temperature on the printer without the filament and the PTFE bowen tube should start to smoke and burn in <50 sec
On my stock Creality Ender-3 the PTFE bowen tube melts and starts to burn when it reaches 260 C that the printer allows out of the box, this commit attempts to decrease the max temperature by changing HEADER_X_MAXTEMP in Marlin to decrease the max safe temperature to 240 to avoid this fire hazard.
This issue can be reproduced by using 260C hotend temperature on the printer without the filament and the PTFE bowen tube should start to smoke and burn in <50 sec