The system filters were changed. (In November the yellow jacket vacuum pump oil was changed.) After filters were changed the compressors were tested.
Left compressor took 11:50 (m:s) to get to 715 psig and shut off automatically. In the ensuing 90 seconds the pressure dropped to 700 psig.
Right compressor took 2:10 (m:s) to get to 770 psig and shut off automatically. In the ensuing 90 seconds it dropped to 732 psig.
Then the system and hoses were evacuated using procedures outlined in the youtube.com videos on the dilo system.