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Gravity hot water diverting tee

Dave_132
Dave_132 Member Posts: 65
in THE MAIN WALL
Does anyone know if this will work with forced circulation ? It is in a 100 year old home and we are changing the boiler. I think that it had an internal diverting casting to send water up on the right and pick up the return on the left. I hope that we wouldn't have to disturb it.

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Comments

  • Paul48
    Paul48 Member Posts: 4,469
    Don't think it will work

    I believe it relies on the different temp layers within the large mains. It does not "scoop" the water like a more modern diverter tee. I believe it was called stratification? You will probably be adding return mains.
  • ChrisJ
    ChrisJ Member Posts: 16,315
    Pump?

    I know close to nothing about hot water heat and am asking this just for my own knowledge.



    Why convert a gravity system over to forced? If it's worked for 100 years why add a pump now being all of the piping is already in place?

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

  • JStar
    JStar Member Posts: 2,752
    Hot Water

    Agreed that you might have trouble adding a pump to this system. I would keep it as gravity. What kind of boiler are you installing? I would use a mod/con feeding a large buffer tank or hydraulic separator with only one pump for the boiler. The storage tank will act like a gravity-feed boiler.
  • Ironman
    Ironman Member Posts: 7,547
    edited September 2014
    Eureka Tee

    It's a Eureka Tee.



    There's a thread on the wall a couple of notches down that's discussing this titled : Old house, diverter Tees.



    http://www.heatinghelp.com/forum-thread/151329/Old-House-Single-pipe-hydronic-with-diverter-tees



    JStars advice about using a buffer tank is good. It's the best solution that we came up with, too.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Steamhead
    Steamhead Member Posts: 17,380
    It should work fine with a circ

    as long as the circ is properly sized to mimic the gravity flow. Size your circ from the chart in this article and you should be fine:



    http://www.heatinghelp.com/article/343/Circulators/238/Sizing-Circulators-for-Hot-Water-Heating-Systems
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Ironman
    Ironman Member Posts: 7,547
    Agreed...

    If using a cast iron boiler which has little or no head. But a mod/con which usually has high head and needs high velocity is gonna need hydraulic separation to work with this type of system.



    Remember, it's not just a gravity system; it's a system that requires stratification in the piping to function.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Dave_132
    Dave_132 Member Posts: 65
    Cast iron boiler

    I plan to use a cast iron boiler with a very low gpm pump and low head. The buffer tank is a good idea however we have space limitations . What is available that would match the old gravity flow and allow the hot water to migrate similar to the old system.

    Has anyone ever been able to determine the flow rate on a gravity system.

    There was an error rendering this rich post.

  • Paul48
    Paul48 Member Posts: 4,469
    Your

    system is not a conventional gravity system. Yours is a one-pipe system. If you could pump it slow enough to ensure the stratification within the main, there would be no advantage to doing so.
  • Steamhead
    Steamhead Member Posts: 17,380
    How many square feet

    of radiation do you have? 
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Dave_132
    Dave_132 Member Posts: 65
    Square feet of radiation

    I will be measuring all the heat radiators tomorrow in order to determine total amount.

    There was an error rendering this rich post.

  • Gordy
    Gordy Member Posts: 9,546
    ChrisJ

    Control is the reason Chris. 100 years ago Fuel was cheap if it got to hot you just opened a window. Today you open a window its like opening your wallet. No one complains only if there is not enough heat.
  • Ironman
    Ironman Member Posts: 7,547
    Flow Rate

    The flow rate will vary depending upon the water temp. As it gets hotter, it will increase.



    If you measure the Delta T between supply and return, and you also know the btu output of the boiler, then you can use the universal hydronic formula to find the gpm.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • icesailor
    icesailor Member Posts: 7,265
    Speeding Pumps:

    Multi-Speed and Variable Rate circulator pumps can be a wonderful thing.

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