Is the system using R22 or R12? R22 General working pressure High pressure 13-15 kg, low pressure 1.2-1.8 kg. The high pressure of R12 is about 11, and the low pressure is 0.8-1.2 kg. The general system is that the air-cooled pipe is not long 8-10 kg, and the pipe is 13-18 kg. Due to the expansion valve, it is not uncommon to add 3 or 4 kilograms of freon, the filling amount and working pressure should be considered comprehensively, such as the frost phenomenon of the return pipe, and the opening degree of the expansion valve and the position of the temperature packet should be not changed during repair.