I have been finding more cases recently of obstructed cap tubes on commercial equipment. All have been with R-134a or R-404a refrigerant. I don't know if it is the POE oil causing the problem. The obstruction is usually partial, causing high superheat. This often causes frosting of the evaporator and ultimately leads to compressor failure. I found a couple of threads relating to a similar problem on domestic refrigerators. The consensus for domestics was to dispose of the refrigerator and buy a new one. That isn't practical with more expensive commercial equipment. Is anyone else noticing these problems?