Worked a really old r12 federal deli case today. Now 414. Several signs i need to add charge, but head pressure as high as i think I should go. (Worth saying condenser is so old it has no fins, just tubing).
Sight glass bubbling alot, sub cool 0 with no receiver. Suction pressure 18 with a 42 degree box. Suction line 53. Frost after txv for about 15 inches of line, but none on evap coil. Unit slowly pulled down from 51 to 41 as i added some gas. However still have above conditions with 160 head at 80 ambient.
So I have several signs i need to add gas, but feel head pressure is already high enough. I know sh is way high?
Is it normal for these old deli cases to pull down real slow? I'm guessing so. Should I attempt to add anymore?
Would love to clear glass, but think head will go to high. Maybe this old ass coil design wont remove enough heat. K body semi hermetic compressor also