Doc,
My operating procedure: Gun on upper shelf, install fill probe or connect to pre-installed male foster, depending on gun design, assure all fittings firmly in place. Check YH oil level, to top of red circle. With compressor at room temp, fill bucket in sink, on stool, install water pump with hoses to compressor. Add three bottles ice, chill water 20 minutes, start water pump, chill compressor to 18s-degree C. Make sure copper-colored filter drain and two pressure-release screws on YH are open, start rear fan on high, start compressor, close three pressure-release screws to snug. (Fan and water pump remain on until fill session is complete, everything cool to touch. Replace ice bottles, as needed.) After fill pressure is reached open three pressure-release screws, let compressor run few seconds, shut off. I wait 45 minutes between gun fills to let everything cool, overheated once going too fast. Usually crack open each of the three pressure-release screws at least once during few minutes it takes to fill each gun, just to vent moisture. Members who fill bottles/tanks might want to share procedures. WM