Russ... This is only one of the reasons to always use a hi side gage, You need to know what's happening while adding. If you are lucky you may not have harmed the expansion area when moisture froze and plugged the system, also you put a very heavy load on the compressor. And you were lucky that a line didn’t bust, You do not want to be hosed down with liquid refrigerant. BEFORE adding, when you start out with little or no pressure in the system, it is very likely that moisture has been drawn into that system. Pull a deep vacuum for at least a half hour or more, to boil out all the moisture. It would seem you were lucky to this point , so you may still be in luck and have a working A/C when you recharge the <span style="font-weight: bold">evacuated, dry, system.</span> KennyV.