Under sink Tankless + water filter questions

Discussion in 'Tankless Water Heater Forum' started by MasterApprentice, Aug 15, 2019.

  1. MasterApprentice

    MasterApprentice New Member

    Joined:
    Feb 24, 2019
    Location:
    Aurora, IL
    Hello;

    I am installing an under sink tankless heater for a kitchen remodel. The reason for the heater is that we have hot water running through a slab and it wastes a lot of water and heat just to get a stream warm enough to wash dishes, especially in the winter. My wife wants a water filter as well and I'm wondering what order I should connect everything up in the circuit.

    I am thinking I can cap the hot water line and run everything through the filter, but I'm not sure if this would limit me in some way I haven't thought of yet. In this case it from the cold water line I would go to the filter then split one line to hot water, which would then feed the faucet and dishwasher. This way all of the water would be filtered.

    Alternatively, I could just run the slab hot line to dishwasher (this water would never even be warm when going into the washer). It wouldn't be filtered, but then everything wouldn't be fed from the cold line.

    Any thoughts?

    Filter will likely be this: https://www.propurusa.com/Inline-Connect-FS10_p_219.html
    And Tankless heater will be this: https://www.homedepot.com/p/Stiebel...less-Electric-Water-Heater-DHC-10-2/203210886
     
  2. Dana

    Dana In the trades

    Joined:
    Jan 14, 2009
    Location:
    01609
    With reasonable water pressure putting the filter up stream of everything shouldn't be a problem. With any tankless the less crud & minerals is better, since they tend to to develop lime and other deposits on the heating elements over time. (If you're on a well, a water softener may also be a good idea.)

    Be sure to install fat enough wiring to this beast. The minimum wiring sizes for the 9KW & 10KW versions is #8AWG, so don't even THINK about hooking it up to a #12 AWG circuit. The 10KW version needs a dedicated 40A/240VAC breaker, which is a large chunk of the total panel capacity for most houses. Make sure you're staying within the limits of the main panel too- you don't want the whole house to go dark occasionally when the dishwasher is filling.
     
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  4. MasterApprentice

    MasterApprentice New Member

    Joined:
    Feb 24, 2019
    Location:
    Aurora, IL
    I'm on city water, so no water softener. Having an 8AWG, 40A dedicated circuit installed next week after I tear out the old cabinets and such.

    I only have 100A service, but the biggest draw is a 25A 240 line for the central AC. Drier, main water heater, furnace and stove are all gas and if I calculated correctly the 40A line will put me at 89A total.
     
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