Hardness for Tankless water heater

Discussion in 'Tankless Water Heater Forum' started by Technomystic, Sep 2, 2019.

  1. Technomystic

    Technomystic New Member

    Sep 2, 2019
    Upper Midwest USA
    What hardness is safe to use in a Navien tankless. Chicago water is 8 grains and a Rinnai needs to be descaled annually (quite a pain).
    I am installing a softener in Indiana to treat well water with 14 grains hardness and 0.3 ppm iron.
    I would like to set my softener to conserve salt but it would result in 2-3 grains hardness.
    Would that clog my Navien with CaCl3?
    It might be cheaper and easier to just set the salt consumption higher to get <1 grain output than to have to descale the Navien.
    What is most efficient hardness please?
  2. Reach4

    Reach4 Well-Known Member

    Sep 25, 2013
    If you set your softener to use 5 or (preferably) 6 lb/cuft of salt, you should do better than your 2 grains of leakage. You would still be getting reasonable salt efficiency.

    With the 6 lb/cuft it will make the water better than going leaner. 8 to 6 is the most popular range.
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