Prius 2011 A/C Overcharge Symptoms

I have a new A/C compressor installed at a local workshop. It worked there but after got home I felt wasn't cold enough. During the day I went to a few places the A/C started blowing hot air, I heard the compressor keeps trying to start, goes on and off every a few seconds. The next morning, when I started the car, the A/C works again. After a couple of miles, A/C went back to the pulsing mode and stopped cooling.

I found this video on YouTube

shows exactly the same symptoms. It turned out the system is overcharged. Now everything makes sense, in the morning after the system cooled overnight, the A/C pressure got lower, the compressor started normally. After driving under the sun, the temperature raised so does the pressure in the A/C system, so it quits.

I used a screwdriver to push down the the Low valve to release some coolant, until the system runs continuous (just a few pchits, really not much), everything is fine now.

 

I watched the video at night, couldn't wait to find out if it would work. If a pchit made no difference I'd stop.

 

The oil came with the compressor bought from carid. The shop used the machine to charge it. I don't think they have much experience with electric compressors so they didn't charge it precisely, as you could see in the video the compressor is very sensitive, just the coolant in the hose is enough screw it up.