Trane 3D Scroll Tandem 50 Ton Split
First post - I'm a fairly green refrigeration apprentice. Had a question on the Trane RAUC C50 EB2 - 50 ton split unit with four 3D scroll compressors, 2 in tandem with eachother (15T with 10T comps in tandem x2). I am just doing a maintenance on the unit and noticed that the sight glass is flashing on the two liquid lines. Now this is occuring when just 1 compressor of the 2 in tandem are running. I was curious as i've never worked on tandem compressors before, and where they share the same liquid line is throwing me off. If just 1 of these compressors runs, would that cause the sight glass to flash? Or is it a sign of being undercharged? I would assume the liquid line regardless would always need the full coloumn of liquid to feed the TX valve and ensure theres some subcooling going on. But then it makes sense that it would flash as the liquid line doesn't change size regardless of one of both compressors running and if just one is running it isn't pumping nearly half the refrigerant feeding that one coil, making it flash in the oversized line. Obviously quite confused. Any help of clarification on how this actually works would be greatly appreciated.