This is an AC R22 Unit for my home. Specifically, the second floor split system. It's a Goodman 2 1/2 ton (Wish I had a 3 ton Now that it was 115 In NYC) and the AC just barely handle this.
Anyway, when the weather cooled off I tested my system to see why it could barely handle this while the exact same system downstairs kicked ass during that time.
I have superheat at 4f or around outside on the blue dial with 55f wet bulb temp. I had to run this higher due to the suction length being over 50' to my attic. I'm using a 3/4 line set but I thinking about getting bigger to reduce the pressure.
My Line Pressure (Red Dial) is zero.nada zilch. I cleaned the entire system and flushed the condenser in the attic out with a garden house for an hour after spraying it with mold spray first. There was little black mold spots in the condenser not allot but it was enough to make me clean it good. The air filter however was so clogged from 5 cats that I don't know how it even worked. It's all cleaned now and almost new again... 5 years old.
When my AC guy put these in they came with a little bag that had a fixed orifice valve. I'm thinking its probably DOA now. I read about TXV are better for my system than fixed valve.
I'm hoping that its only a clog in the line from the fixed orifice valve but I can't see it being anything else since I'm able to get pressure from the suction line with no problem.