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Gravity System Boiler Replacement

IronmanIronman Member Posts: 5,300
edited November 2017 in THE MAIN WALL
Started replacing this original boiler (1933) on a gravity system last week. This house is being almost completely gutted and rehabbed. My contract was just to do the boiler, indirect and near boiler piping. The owner has decided to remove two large rad's from the kitchen and move another one in a room in the basement. As they began to demo walls, we found that the piping for three other rad's on the 2nd floor would have to be redone. The system also has a boatload of sludge because it never had an expansion tank: an air cushion was left in the top of the rad's causing the sludge. We've seen it before on this type of setup.

Since all this moving and repiping is gonna be T&M, and because of the sludge, I think I'm gonna propose getting rid of the large pipes and going with a home run system with manifolds.

Pics posted in reverse order.





Bob Boan


You can choose to do what you want, but you cannot choose the consequences.
«1

Comments

  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 6,103
    Amazing how long those old boilers held up. Wish the new stuff held up half as long
  • ZmanZman Member Posts: 5,333
    Very nice Bob!
    I love the Black...
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 6,103
    I like the LL header. Why buy what you can make cheaper?
  • Danny ScullyDanny Scully Member Posts: 1,219
    Yea @EBEBRATT-Ed, labor doesn’t cost anything :wink:
  • njtommynjtommy Member Posts: 1,105
    Nice work. Can’t beat some big old headers and cast rads
  • bob eckbob eck Member Posts: 893
    Did you flush the system? Are you not installing a dirt magnet? What size is the P/S unit 2” or 3” and what size air vent is going on top? Were you able to find a mesh to put into the P/S separator?
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 6,103
    @Danny Scully , gee, I guess you don't like my comments either. I won't be able to sleep tonight. Thought the pipe and fittings just screwed itself together
  • IronmanIronman Member Posts: 5,300
    To clarify a couple of things: the main reason I'm considering repiping with a home run system is because of the imbalance that's being created by the removal of several rad's and the amount of repiping that needs to be done.

    We do a lot of conversions on these old gravity system and one thing that has to be carefully regarded is system balance. The dead men made sure of this when they built them. Just changing them to forced flow alone can cause unexpected issues if this is not observed.

    This system is being thrown out of balance by the unexpected and unannounced changes that the HO is doing in spite of my repeated warnings. THAT, plus the amount of sludge that's in the system is what's driving me to want to repipe this with a home run system with manifolds. That will allow me to regulate the flow to each rad, zone it into 2 floors and get it properly balanced.

    Not to be unkind, but I think that I've been on here long enough and known well enough to know that I would do proper flushing and dirt filtration.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 6,103
    Nice job @Ironman , I am sure it will work well
  • Solid_Fuel_ManSolid_Fuel_Man Member Posts: 1,754
    Looks clean and professional. I agree if it's all cruded up and now out of balance, I'd repipe some or all as well.
    Serving Northern Maine HVAC, and Controls
  • IronmanIronman Member Posts: 5,300
    I met with the owner today and he agreed to repipe it.

    I'll post more pics as we progress.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • njtommynjtommy Member Posts: 1,105
    So repipe and trvs aswell?
  • IronmanIronman Member Posts: 5,300
    No TRVs, just repipe into 2 zones.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • Jamie HallJamie Hall Member Posts: 11,425
    Good show, @Ironman -- sometimes it can be difficult to convince people to do things right.
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • IronmanIronman Member Posts: 5,300
    I think the "cheap gene" drives most all of us to some degree. Fortunately, this customer has a lot of faith in my expertise and when I explained that I couldn't guarantee how the system would perform unless we re-piped it, he saw the wisdom in doing it. Prayer helps a lot too.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • Nice job and I'm glad the owner relented. Whew!

    Don't you think the issue would have the same outcome just by adding TRV's?
    Often wrong, never in doubt.

    Click here to learn more about this contractor.
  • IronmanIronman Member Posts: 5,300
    edited November 2017
    Kinda doubt it. And pulling spuds out of 16 rad's would have been a lot of work and $$. Plus, I still would have had to re-pipe three rad's on the second floor to the basement, and move and re-pipe one in a basement room.

    This system was really sludged up; the mains were about half full with it.

    It is hard to get people that don't understand hydronics to realize that just because it has pipes connected to it, doesn't mean that it's gonna work. When I asked the owner what he would do after all the walls were closed and something didn't work right, he realized that re-piping was the prudent thing to do.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • Brilliant!
    Often wrong, never in doubt.

    Click here to learn more about this contractor.
  • Solid_Fuel_ManSolid_Fuel_Man Member Posts: 1,754
    I've only read about it here on HH, never come across a system which relied on trapped air in the rads to act as an expansion tank. I honestly wonder what the rationale was behind not having an expansion vessel somewhere.

    Not everything the dead men did worked out, but i guess it outlasted them.....
    Serving Northern Maine HVAC, and Controls
  • Are you sure there's no expansion tank in the attic? We have a lot of old gravity systems out here and they all have them.
    Often wrong, never in doubt.

    Click here to learn more about this contractor.
  • KC_JonesKC_Jones Member Posts: 4,267
    Ironman said:

    K
    When I asked the owner what he would do after all the walls were closed and something didn't work right, he realized that re-piping was the prudent thing to do.

    If they needed any convincing you could always show them these pictures. I bookmarked this one because I just can't believe it.

    Lucky for your customer they listened to wisdom.

    https://forum.heatinghelp.com/discussion/157697/hot-water-boiler-and-system-repipe#latest
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    https://www.facebook.com/media/set/?set=a.10202744301871904.1073741828.1330391881&type=1&l=c34ad6ee78
  • Solid_Fuel_ManSolid_Fuel_Man Member Posts: 1,754
    Oh I remember that thread! Was a real deal extraordinaire for sure.
    Serving Northern Maine HVAC, and Controls
  • IronmanIronman Member Posts: 5,300

    Are you sure there's no expansion tank in the attic? We have a lot of old gravity systems out here and they all have them.

    Positive, we've encountered these before around here. Dan has an article about them in the resource center.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • IronmanIronman Member Posts: 5,300
    Making progress. All of the old gravity piping is gone (except risers). All rads and risers flushed and stated running pex-al-pex this afternoon.
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • Paul S_3Paul S_3 Member Posts: 1,257
    Nice job @Ironman
    ASM Mechanical Company
    Located in Staten Island NY
    Servicing all 5 boroughs of NYC.
    347-692-4777
    [email protected]
    ASMHVACNYC.COM
    https://heatinghelp.com/find-a-contractor/detail/asm-mechanical-company
  • JUGHNEJUGHNE Member Posts: 6,175
    Solid Fuel Man, I have an old 2 story house now used as an office on the lower floor.
    I leave the 2nd floor rads with air in them to just not heat the rooms completely. The lower portion has water flow and stays warm enough to prevent freezing. The bathroom is fully bled of air.

    For the dead men this avoided the expansion tank and piping.
    Also it kept the water from being exposed to fresh oxygen.
    Also perhaps a little better temp control on the 2nd floor.
  • IronmanIronman Member Posts: 5,300
    We don't have everything connected yet, but it's up and running.



    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • GordyGordy Member Posts: 9,346
    I like that iron hydraulic seperator!
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 6,103
    @Gordy , glad you liked it. I did too in an above post, some didn't like it. Thought it was a great idea and looks good too!!
  • GordyGordy Member Posts: 9,346
    edited December 2017
    ^whats not to like. Black pipe isn’t cheap, but it’s cheaper than copper, and, brass, or the real deal. Shows ingenuity in use of off the shelf resources with little modification to make a hydro sep. well done in my book. I also like how it gels in with the black backer board.

    Add some rare earth magnets to the can, and get ferrous metal capture.
  • jbeckjbeck Member Posts: 15
    @Ironman
    What is your method of flushing the radiators and risers?
  • bob eckbob eck Member Posts: 893
    What brand pex did you run?
  • bob eckbob eck Member Posts: 893
    Have you used many HTP boilers? Any issues with them? Are you using their condensing boiler or combi boiler?
  • SuperJSuperJ Member Posts: 556
    Is there any meaningful loss in efficiency from bundling supply and return PEX/PEXALPEX into the same bundle? I tend to keep supply/return separate, but have never figured out if it makes a difference?
  • clammyclammy Member Posts: 2,350
    Great looking job a lot of time ,thought and craftsmanship way to go .like the way u used the pvc as bundle supports for the pex excellent attention to detail n love the mimiunism everything serviceable .enjoy the photo w all the tools n crap all over the place makes me not feel when in the mist of things bad organized dis order I call it ,end product is what matters not how neat it is while it’s happening .peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • IronmanIronman Member Posts: 5,300
    bob eck said:

    Have you used many HTP boilers? Any issues with them? Are you using their condensing boiler or combi boiler?

    Only a couple of minor issues: one had a board that would recognize a domestic call. Another had a broken flap on the blower outlet. HTP has a TSB about this.

    As a rule, I don't do combi's.

    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • IronmanIronman Member Posts: 5,300
    SuperJ said:

    Is there any meaningful loss in efficiency from bundling supply and return PEX/PEXALPEX into the same bundle? I tend to keep supply/return separate, but have never figured out if it makes a difference?

    I don't think so, but I think the only way to know would be a scientific study and who's gonna do that?

    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • IronmanIronman Member Posts: 5,300
    bob eck said:

    What brand pex did you run?

    It's Pex-Al-Pex. I don't remember the brand.

    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • jbeckjbeck Member Posts: 15
    edited February 25
    @Ironman
    What is your method of flushing the radiators and risers? Can it be done while connected to the boiler? (I assume you didnt take each radiator outside and flush with the hose)

    I took a sample of my boiler water - when i place a magnet against the water, all the black specs are attracted to the magnet.
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