Here’s an easy way to set preheat temperatures on a Prusa.
Keep a file on an SD card to set your desired preheat temps, and “print” it from the Prusa menu. For example:
M104 S170 ; set hotend temp to 170C, and continue without waiting
M140 S75 ; set bed temp to 75C, and continue without waiting
M84 ; disable motors to prevent popup showing that file is incomplete
M73 P100 R0 ; set print progress to 100% and time remaining to 0
170 and 75C work well with my i3 MK3. The nozzle won’t drool much, and when the print is launched both bed and nozzle will reach the final temps at about the same time.
Preheat temps can of course be set directly through the Prusa menu, but sometimes I find it more convenient to print a file from the SD card instead.
M104 S230 ; set hotend temp to 230C, and continue without waiting
M140 S0 ; set bed temp off, and continue without waiting
M84 ; disable motors to prevent popup showing that file is incomplete
M73 P100 R0 ; set print progress to 100% and time remaining to 0
M104 S0 ; set hotend temp off, and continue without waiting
M140 S0 ; set bed temp off, and continue without waiting
M84 ; disable motors to prevent popup showing that file is incomplete
M73 P100 R0 ; set print progress to 100% and time remaining to 0