a hot fill apparatus for use in the testing of hollow thermoplastic containers , the apparatus having a reverse osmosis filter system , a heater system and a fill head system . the reverse osmosis filter system removes chlorine and other particulates and contaminants from the water prior to the water entering the heater system . the heater system is designed to maintain strict temperature control of the water while maintaining a steady flow rate and pressure . the fill head system includes a manually operated spigot and an automatically operated fill head , the operations of which are mutually exclusive .