Another scenario,if anyone can answer.
Checked a chiller and found low subcooling( well the manufacturer did) with an ambient of 9°C, he added some R134A, system was at 100% load.

Two weeks later another manufacturer employee went out and said it was over charged, reclaimed the gas and said it had been overcharged by 2kgs(64kg charge).
I was not sure what the ambient or pressures were as i did not attend.
Someone explained that as the ambient was lower the subcooling coud have been low and as the ambient was probably higher the 2nd time around and had been overcharged the subcooling would have been low again because of the liquid backing up in the condenser.
How can you have effectively have the same scenario ( low subcool) and have two different answers.