I'm currently in Iraq and trying to recover several small, split-system room A/Cs from a combat outpost we're closing down so we can take them with us to the next place. I've researched the subject to the best of my abilities on the internet and probably know just enough to be dangerous and screw it up. I know I need to hook up a pressure gauge to the service port on the low pressure side, close the narrow tube service valve and let the A/C run in cooling mode until the pressure reaches 14.2 - 7.1 psi. The problem is...I don't have a pressure gauge. I read something about some A/Cs having a low pressure switch that will shut off the A/C once it gets to 7.1 psi. Does anyone have any suggestions on how I can do this without the pressure gauge? These A/Cs are coming with us, whether they work or not, though I would obviously prefer to be able to take them with enough refrigerant to make 'em blow cold air again (it tends to get a bit warm here).
Thanks for the help.