Navien Inc. has introduced three chemical-free and environmentally friendly products to refresh its PeakFlow lineup of scale-prevention solutions. PeakFlow S, PeakFlow A and PeakFlow C expand the options made available by Navien to now include point-of-entry and commercial- grade scale prevention. PeakFlow S (standard) is a point-of-use residential solution installed at the cold-water supply line before the water heater to prevent scale buildup within a water-heater system for a flow rate up to 6 gallons per minute. PeakFlow A (advanced) and PeakFlow C (commercial) can be installed at the cold- water line leading into a water-heater system to prevent scale buildup for flow rates up to 10 gpm (PeakFlow A) or 20 gpm (PeakFlow C). PeakFlow A also can be installed as a whole-house point-of- entry system that helps prevent scale for all water flowing through a house. PeakFlow C is designed specifically for commercial water-heating systems that need to prevent scale at larger flow rates.