Follow along to answer the question "What is the blue liquid in the water tank and water tubing?"

Graco water tests and then prepares each unit for packaging and storage so that it can be sent anywhere in the world.  Transportation and storage temperatures have to be considered, so each unit is protected with Windshield Wash Fluid in the water lines, the water tanks, and the pressure pots.

Windshield Wash Fluid is used for protection against freezing because it evaporates on contact with the substrate during blasting, leaving no residue.

The Windshield Wash Fluid can be left in the water tank when you fill the tank with water.  It will be diluted to the point of leaving no residual on the substrate being blasted.

If there is any possibility of freezing temperatures during the storage of the unit (even just for one night), the unit should be fully winterized as instructed in the manual.