Navien introduces PeakFlow, a new chemical-free anti-scale water treatment accessory that is an environmentally-friendly alternative to traditional water softeners. PeakFlow provides protection from scale formation on plumbing surfaces in appliances and hot water systems. The pre-installed inlet ball valve on the 15-lb. single cartridge has isolation shutoff and filter changes. PeakFlow is certified to NSF/ANSI Standard 42 and 61. Navien.