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divert flow to second floor from basement with single pipe method

shredmaster
shredmaster Member Posts: 26
edited August 2020 in THE MAIN WALL
I'm converting steam heat to the hot water heater in an old house. I'm trying to avoid opening up the walls and drill holes in the joist or stud on my second floor.

If I have the loop in the basement, then send the flow to the second-floor radiator (12 ft elevation, boiler to basement ceiling + first-floor hight) and return back to the loop in the basement. would that work? a friend suggests having diverter tee on the return and supply. I don't know if that true because the static head is zero (aka elevation pressure drop) in the close system. A single diverter tee should still work regardless of elevation between the loop and the radiator.

here is the illustration of setup.

Comments

  • Normally, a single venturi should work. You just have the pressure drop of the piping and radiator to overcome. What size is the condensate return?
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    shredmaster
  • Jamie Hall
    Jamie Hall Member Posts: 23,162
    Pity you are converting. It would almost certainly have been considerably cheaper to bring the steam system back to what it should be -- but that's your choice.

    I assume that this was a two pipe system? Be sure to remove any traps or orifices which may be associated with the radiators. Also be very sure that your pipe sizes -- particularly the old return pipes -- are adequate for the flow needed.

    In my opinion you will save yourself a great deal of headache if you add bleeders to all the radiators. Otherwise -- particularly if you are using diverter Ts or venturis, rather than dedicated supply and return piping -- you may find that getting air out of the system is, bluntly, impossible.

    Be sure to pressure test the entire system to the pressure relief valve setting on the new system (not operating pressure).

    You may have some very interesting balancing problems.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    HVACNUTmattmia2ethicalpaul
  • shredmaster
    shredmaster Member Posts: 26
    edited August 2020

    Normally, a single venturi should work. You just have the pressure drop of the piping and radiator to overcome. What size is the condensate return?

    the supply header is 1" from the boiler with 3 zones, second floor 3/4" to overcome extra pipe length, first floor and basement will be 1/2" and the returns will stay the same.

    in a single pipe method with diverter tee(not series), how do you calculate the amount of flow that will divert to the tee that goes to the radiator?
  • HVACNUT
    HVACNUT Member Posts: 5,804
    Sounds like a can of worms. Pipe homeruns back to new manifolds. 
  • shredmaster
    shredmaster Member Posts: 26
    edited August 2020
    HVACNUT said:

    Sounds like a can of worms. Pipe homeruns back to new manifolds. 

    definitely worth considering. I have 4 rad on the second floor and 6 on the first floor and 2 on the basement. maybe get a 4 in/out manifold for the second floor and other two zones still using loop method? or get a 12 in/out manifold and run everything separately which means there is will significantly more pipe.
  • Jamie Hall
    Jamie Hall Member Posts: 23,162
    "in a single pipe method with diverter tee(not series), how do you calculate the amount of flow that will divert to the tee that goes to the radiator?"

    There isn't a simple method. The split in flow will depend entirely on the head loss through the two circuits; flow will split in such a way that the head loss will be the same. In a normal monoflo system, there are some general design rules which work moderately well. If the piping and fittings -- never mind the radiators instead of fin-tube -- it can be done -- to a first approximation, but even that is not simple.

    Worse, in a complex piping situation, it is unlikely that the flow split will be stable. As @HVACNUT says -- save your sanity and pipe it as a home run system to new manifolds with flow balancing valves.

    Or better, if you haven't already started the demolition of the steam system, think again...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    mattmia2
  • shredmaster
    shredmaster Member Posts: 26
    edited August 2020

    Pity you are converting. It would almost certainly have been considerably cheaper to bring the steam system back to what it should be -- but that's your choice.

    I assume that this was a two pipe system? Be sure to remove any traps or orifices which may be associated with the radiators. Also be very sure that your pipe sizes -- particularly the old return pipes -- are adequate for the flow needed.

    In my opinion you will save yourself a great deal of headache if you add bleeders to all the radiators. Otherwise -- particularly if you are using diverter Ts or venturis, rather than dedicated supply and return piping -- you may find that getting air out of the system is, bluntly, impossible.

    Be sure to pressure test the entire system to the pressure relief valve setting on the new system (not operating pressure).

    You may have some very interesting balancing problems.

    what kind of toll

    "in a single pipe method with diverter tee(not series), how do you calculate the amount of flow that will divert to the tee that goes to the radiator?"

    There isn't a simple method. The split in flow will depend entirely on the head loss through the two circuits; flow will split in such a way that the head loss will be the same. In a normal monoflo system, there are some general design rules which work moderately well. If the piping and fittings -- never mind the radiators instead of fin-tube -- it can be done -- to a first approximation, but even that is not simple.

    Worse, in a complex piping situation, it is unlikely that the flow split will be stable. As @HVACNUT says -- save your sanity and pipe it as a home run system to new manifolds with flow balancing valves.

    Or better, if you haven't already started the demolition of the steam system, think again...

    already demo the steam system. any recommendation for a 12-loop manifold. should i get a single manifold or manifold for each zone (floor)
  • Jamie Hall
    Jamie Hall Member Posts: 23,162
    Pretty sure you're on your own here. I recommend -- very highly -- that you study everything Caleffi offers about hot water heating (or, perhaps, hire a really good pro.). You need to pipe your system with individual home run loops for each radiator in a primary secondary configuration. You can get fancy and run separate zones (either zone valves or zone pumps) or... lots of possibilities.

    However, as I said in one of my earlier posts, before you do anything else -- anything else -- you need to ensure that the radiators will work at all with hot water (not all do) and that all the steam-related devices are removed (traps, orifices, etc.) and that the necessary hot water bleeders are added to the radiators. Then pressure test the piping and radiators you are going to use. The pressure test must go to the relief valve setting -- usually 30 psi.

    Please do yourself a favour and do this before you spend any more money. You've already spent what it would have cost to restore the steam system to glory in tearing it apart; don't waste any more now that you don't have to.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    mattmia2shredmasterethicalpaul
  • shredmaster
    shredmaster Member Posts: 26
    edited August 2020

    Pretty sure you're on your own here. I recommend -- very highly -- that you study everything Caleffi offers about hot water heating (or, perhaps, hire a really good pro.). You need to pipe your system with individual home run loops for each radiator in a primary secondary configuration. You can get fancy and run separate zones (either zone valves or zone pumps) or... lots of possibilities.

    However, as I said in one of my earlier posts, before you do anything else -- anything else -- you need to ensure that the radiators will work at all with hot water (not all do) and that all the steam-related devices are removed (traps, orifices, etc.) and that the necessary hot water bleeders are added to the radiators. Then pressure test the piping and radiators you are going to use. The pressure test must go to the relief valve setting -- usually 30 psi.

    Please do yourself a favour and do this before you spend any more money. You've already spent what it would have cost to restore the steam system to glory in tearing it apart; don't waste any more now that you don't have to.

    probably better off hiring a pro, thanks a lot for the advises.
  • dopey27177
    dopey27177 Member Posts: 887
    What you are attempting to do is a little over the top. The installing of a hot water system by using the hot water from the boiler to install a new zone was not meant to install a diverter (t).
    You can run the piping as a home run to all the radiators up to 40,000 BTUs with 3/4" pipe. I think pushing 1" pipe is a bit of a stretch.

    See the proper pipe installation for using the the boiler water for H.W. heating. Additionally, The writing covers other items and the physics of this type of installation.

    Jake

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,713
    @dopey27177
    I believe that there is no steam boiler anymore.
    Maybe I am reading this wrong but I believe the new boiler will operate the existing radiators by using hot water.

    @shredmaster
    One thing to consider. The new water temperature will be lower than the steam temperature that heated the space. You may need to set the High Limit control to 210°F to get enough heat for the space. Each radiator will be smaller (in output) based on your new plan.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics