in theory. i wouldn't necessarily trust it, and he needs to have it recovered, oil added, vacced, leak checked and refilled anyway as he now has an unknown charge.

rollinz, you clearly know a bit about this, but 1 minute without any forced air cooling over an automotive condenser will definitely over pressurise until the HPRV blows off. believe me, i worked for the manufacturer of the compressor on his car, Sanden, for 12 years and have done various tests where we deliberately did things like this.

you are right that a blockage would also cause a similar effect to the high pressure side if the clutch was overridden, but a simple blockage would still give a balanced pressure sufficient to switch the compressor on in the first place which is not happening - hence most likely to be pressure switch failure.

maybe your robinar machine doesn't tell you that?