Brian, this ones for you

Came across a high wall unit today, fitted by a plumber no doubt. Was a Mitsubishi, my question is:

Where does the refrigerant start expanding? At the condensing unit end or at the evaprator?

I know, in my experience they expand at the condensing unit end, hence, both lines insulated. This one wasnt. Had a 1/4" pipe, uninsulated, and I think a 5/8" or 1/2" insulated. I presumed the low pressure would start at the condensing unit end, pressure was a high 70 psig. The pressure on the return pipe, 5/8" sizxe was in deep vacuum.

It completely befuddled me