What is the best way to fix a problem where 410A was charged instead of R22 in a unit that was 2 pounds short of refrigerant.

What is the best way to fix a problem where 410A was charged instead of R22 in a unit that was 2 pounds short of refrigerant.

Evacuate the system with a vacuum pump after recovering the 410a, then put a proper charge of R22. I would recover to an empty tank as that one is now contaminated. And mark it clearly as such.

You will definitely have to get rid of all the gas and vacuum down the system; however, if it was short of gas there has to be a leak and you need to find that first. It could also be that the inside coils are clogged up with dirt (along with blower fan) which causes the suction pressure to drop. Most jackleg ac people just pump more Freon in the unit to raise pressures which ruins the compressor so they have a reason to replace the whole unit rather than clean it and prevent all of this.