what psu should i be running?

got a original ender 3 for free but it was missing pieces.

so i bought a psu and put it in the printer.

but now it takes a reeeeeaaaaaaallllly looooooooooo HEATING FAILED PRINTER HALTED THEMAL RUNAWAY DETECTED

i have already done 2 seperate PID tunes for the hot end, cant tune the bed due to the lovely creality3D v1.1.4 board.

i was reading that this can be related to using a 12v psu instead of a 24v psu.

is this true? getting mixed messages online.