Thanks for the replies so far. I see 2 fittings. One is a knurled fitting on the flat top of the left side of the compressor (facing the compressor) and a capped hex nut on the end of a tube coming straight out from the top front of the compressor. Is the the fitting on the top left side of the compressor itself the low pressure fitting? Is the high side the other fitting? A friend who has done this on other older makes is doing this for me, but I want to see for myself that is connected properly. Thanks.