Noritz Water Treatment Guidelines
There are several technologies used to treat hard water either by changing its chemical nature or by removing scale producing ions. Noritz America offers two such scale treatment devices: the Noritz H2Flow and the Noritz Scale Shield. Refer to the below tables for suggested treatment and maintenance measures to be taken based on the water hardness level.
A detailed flush procedure may be found at http://support.noritz.com/article/faq-how-do-i-flush-the-heat-exchanger-48.html
Or please visit http://www.noritz.com/home-owners/find-a-servicer/ to find a local Service Representative.