Hi all
I have witnessed an unusual white substance appear in the liquid line sight glass of a 150 kilowatt commercial air conditioning unit. The sight glass is positioned 3 inches after the liquid solenoid and 6 inches before the expansion valve. When the unit is running it is fine, the sight glass is clear. As soon as the unit cycles off or unit is shut down the white haze will instantly appear on the inside of the glass. It appears crystalline, translucent and seems to be about 1 millimetre thick. I do not believe it is moisture. Can anyone shed some light on this?