Replacing 3 tanks to tankless

Discussion in 'Tankless Water Heater Forum' started by My well water, Jun 21, 2017.

  1. My well water

    My well water New Member

    Joined:
    Oct 18, 2014
    Location:
    Texas
    We are moving into a new home in Houston TX that was just built. Water avg is 70 at the tap. The builder put three 40 gal short water heaters in the attic. 2 are in series. I have a one inch gas line that splits to the 3 Heaters. Before we move in I am going to replace them with one Tankless heater. Theoretically saving 400+ a year on the gas bill. Each energy star label has them using $225 yearly. I've had tankless units in 2 of my past 3 houses and like how they work.

    I think it will be the Takagi TH3DV. I was also looking at the Rinnai RUC98iN


    How do you terminate this through the roof? Since I already have 3 exhausts for the tanks in place now. The attic is not tall so it will be about a 5 ft. run. For the condensate line I will add a neutralizer and send it to a bathroom drain with the ac line.

    Thanks
     
  2. Stuff

    Stuff Well-Known Member

    Joined:
    Mar 7, 2013
    Location:
    Pennsylvania
    Sounds like replacing with tankless is a waste of money. The energy star label assumes you are heating water from a colder source and is in a cooler space.

    The tankless instructions will include options on terminating through the roof. You will need to patch the holes for removing chimneys for the old tanks.
     
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  4. My well water

    My well water New Member

    Joined:
    Oct 18, 2014
    Location:
    Texas
    I was going to just leave the extra chimney as is almost like a vent. I figured I can sell the 3 water heaters And I don't care for hot water tanks in the attic.
     
  5. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    I agree that the tankless will probably not save any energy. Also a well pump cycling on and off will sometimes cause a tankless water heater to turn on and off, giving shots of hot and cold in the shower. Keeping the pump from cycling will solve that problem and all the others that occur from the pump turning on and off.
     
  6. My well water

    My well water New Member

    Joined:
    Oct 18, 2014
    Location:
    Texas
    I should change my user name. we moved and are now on city water
     
  7. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Yeah that makes a big difference for an instant water heater.
     
  8. Master Plumber Mark

    Master Plumber Mark Sensitivity trainer and plumber of mens souls

    Joined:
    Feb 6, 2005
    Occupation:
    Sensitivity trainer.. and plumber of mens souls
    Location:
    indianapolis indiana - land of the free, home of

    I totally agree with you on this because the heaters are up in the attic and are basically heating up through
    Passive solar radiation and the intense heat in the attic......
    Your present system is dog-dirt-cheap.... The only thing you have to worry about
    with the 3 short heaters is their age and being sure they are in decent catch pans that go to drains in case of leaking..

    Right now , You have a VERY simplistic PASSIVE SOLAR system at this
    point and switching to a Tankless will not save you a dime.
    If I were buying your house , For a more passive system I would actually install a 300 -600 foot coil of wirsbo aqua-pex in the attic in a pan to feed the water heaters solar heated water on the cold inlet and I think the heaters would probably never fire up very often.... You cant beat FREE.....

    Also you better check into the levels of heat that the tankless circuit board can handle... The attics in Texas can get as hot as 135?? or hell itself??

    I know that this is falling on deaf ears and their is no convincing you to re-consider this decision, and you are probably hell bent on doing this
    just think this through for a while.

    With all due respect, you are basically making things harder and will never see a pay back on this.....



    good luck.
     
    Last edited by a moderator: Jun 24, 2017
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