2002 S60 Refrigerant High or Low pressure?

[sergio]

Something strange happened this afternoon. I decided to first check the state of the refrigerant. I plugged the gauge and read it. The needle went right up to 80 PSI, middle of the red zone!!!

It shows MUCH more gas/liquid in there that there should be.
How could this be?

.

[jimmy57]

was the engine running with compressor engaged when you red this pressure? The pressure in the system equalizes with compressor off and then the pressure is proportional to ambient temp.
On a 80 degree day the refrigerant pressure will be 80 ish psi if the system has at least 25% charge level. This system off pressure is pretty meaningless.

[sergio]

As a matter of fact the engine was not running, and you confirmed my suspicion.

I pulled the relay out, made a short with a wire and when I turned the engine on, the clutch engaged and cold air poured out.
I measured the PSI with engine "on", AC "on" and fan blowing. It oscillates between 27 and 30 PSI. This is the blue zone "FILLED" (25 - 45 PSI)
Should I go all the way up to 45 PSI?
45 to 65 is yellow "ALERT"
Above 65 it is red "WARNING"

I'm not very comfortable with this very short hose, can't even hold the can straight up, vertically.
It is refilling process slow? 5 minutes or 15 minutes.

Later I also tested the relay itself. When applying 12 volts it clicks clearly. So relay must be OK.

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[abscate]

You need to fill and monitor temperature differential inside, blower on high, idle at 1500 rpm, recirc on. It's hard to do by yourself but these pressure readings with all these other variables just don't mean much.

[sergio]

.
OK, I refilled enough gas so that the needle went from 25 PSI up to 45 PSI "ALERT" / Yellow zone.

The clutch is still not engaging.
I still have ECM-5000 A/C pressure sensor - Signal too low
VIDA reading;
ECM-A/C Pressure : 14 PSI (the gauge reads 45 PSI)
ECM-A/C compressor active : Off
ECM-Ambient Air Temperature : 57 (it is 75 on the thermometer on the wall !!!!)

A modest /shy tap with broom stick to the face of the compressor did nothing.
Could it be the sensor, if there is any? Or shall I try to shim the clutch?

.