My salon AC will start most of the time, but maybe 25% of the time it takes a few tries to get the compressor going. I can see it pulling what I assume is locked rotor current when it tries but doesn't start, around 38A). Could this be the starting capacitor needing replacement? I would have thought that it wouldn't start at all, but maybe the capacitor gets week over time?
A friend of mine had the same or similar problem. His AC would start run & shut down then came up with error code panel. It sometime took a few tries to start. His AC manual recommended cleaning strainer & flush the water system with a 7% muriatic acid & water mixture? He used a 5 gallon bucket & pumped into the intake through the system & back into the bucket. He noticed a change in color in the water mixture after running it for about 10 - 15 min. After the cleaning the AC ran good again. Not sure if this will work for you but it might be worth a try?
The cooling water has nothing to do with the compressor starting. High pressure shutdown after a short run time, absolutely. But nothing to do with getting the compressor to start initially.
Yes, caps can get weak. It's more likely that they work fine until they suddenly die, but I have seen old capacitors that measure only 50-60% of their rated microfarads. Also possible is the compressor is on its way out.
Of the two options, only one is quick, cheap, and easy to fix (or rule out). I know what I'd start with.
You mentioned it's a rotary compressor? How old is the unit? If over 10 yrs and it's a rotary, it's time to shop.
Sorry. But the rotary compressors just don't hold up as well.