Found this a couple days ago when I was pissed that I didn't have AC and that my system hadn't been retrofit but had been filled with R134.... 2 cans on 5/5/05 and another 3 cans on 6/27/05 before I bought it... needless to say, I think I'm low on refrigerant.
http://filebox.vt.edu/j/jagibbs/webp...conversion.pdf