Im working on an ice cream display case. Inside the case will not cool down, only about 10% of the evaporator is getting cold (where the cap tube enters) the rest is warm to touch. There is a hissing sound where the cap tube enters and it is frosted over. My guages show the LP as 0 bar (about -40C or so for 404A) and 12 bar for the HP. The weird thing is that when I cut off the machine, the LP immediately goes up from 0 bar to 5 bar and the HP goes down, telling me, I think, that the pressures are meeting each other. I suspected an obstruction in the cap tube, but why would the pressures equalize so fast? Is this superheat pushing down the suction valve? I also suspected bad compressor valves (hermetic), but what about the problem with the evaporator, would this be a symptom of bad valves? Also, I noticed that the suction access valve tube was warm to touch, but Im getting 0 bar, and doesnt that correspond to a low temp.? How could the guage be reading 0 bar with a warm access tube? Shouldnt the tube be cold? Thanks for any help!