My question was not about pressure setting which are relevant only to model of a heat press you used when making Printing Instruction. The values 2-5 bar mentioned in your Instructions convey no information to people using presses different from yours. Moreover, using these recommended settings in air-driven presses with different platen size, and piston diameter in air cylinder, they could not get expected result, because actual pressure P on material could be several times bigger or smaller. In specifications for manual mechanical and pneumatic presses like Sefa (http://www.sefa.fr/fiche.asp?id=127&ID1=18&ID2=17) it is written, that they can create maximum pressure on plates about 0,4-0,5 bar, pneumatic presses like PHP-45-V-2 ( http://transferpress.eu/php_45_v_2 ) – about 1 bar, so if owners of above mentioned presses try to create 3 bar as you recommended, they have good chances to break their machines.
I was asking about pressure on heat platen P=F/S= Ps *Sc/S, where F is pressing force, Ps – system pressure which mentioned in your Instruction, S – square of heat press platen. Normally manufacturers of professional heat presses write in specifications max value of pressure which could be created on platens. System pressure mentioned in your instructions, related to actual platen pressure, the same way as car speed related to RPM (engine rotation speed) displayed on your car dashboard.