They are connected to a 240 volt power source, a cold water supply line, and a hot water pipe that is equipped with a thermostat. The unit is turned on and the temperature of the water produced by the unit is measured at several flow rates to insure that the proper temperature rise specifications are met and that the unit self-regulates with the varying flow rates. Once the unit has passed the above tests, the water is forced out by a high pressure air hose and the unit is double boxed for shipment. It is likely that when you receive the unit you may notice a small amount of water left in the pipes. This is normal and is not an indication that the unit is 'used' or 'reconditioned'.
All units shipped are 'new' unless otherwise labeled.