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Joatmo2
Joatmo2 Member Posts: 6
Converting 1 pipe steam with hot water coil, and baseboard,to forced hot water. Bsmt already has fhw baseboards I built using boiler water to circulate with a tempering valve. Worked fine but old boiler doing hot water is expensive. Plus I think it's way oversized.

Any I've been getting all sorts of heating guys telling me all different things like get two boilers it will be cheaper. Total home runs needed, don't use hepex. Monoflo, in and out on bottom no good.

Giving up and decided to plumb it myself and order a boiler and have the plumber come and do the finishing touches. Like the manifold, boiler and,pumps.



1. Had to get fhw radiators as mine were steam type. I got similar btu size on the assumption that my house was built in 1895 with no installation. And now has installation blown in, siding, double pane windows. I'm using the btu loss of the fhw radiator equals the btus now needed for this room. I also used a btu room calculator to prove my hypothesis. I'm also assuming that my boiler was installed in the 50's or has been replaced, but this was pre insulation . It is rated at 100k btu's so I believe this to be overkill for 1350 square feet with dhw. (Before finished bsmt of 800 square feet). Also this is a two family with two 100k boilers steam+dhw and I want to combine for one boiler. 2nd floor will be baseboard.

Used a couple of of programs and came up with an average of 1000sf = 24000 btu's in state of mass for a well insulated house. Both floors and bsmt = 3500 sq ft =84000 btu's.

Am I misunderstanding, bad at math, or what. How wrong am I????. Then the debate of btu upsizing for dhw . I would like to get a http contender 120 btu mod/con boiler. Which modulates between 44 to 120 btus. I think I'm factoring in everything. Please help all comers resent my questions, and just want to give me a huge price 30 to 40 k.



2. Pex and piping "......... I can repipe most of the radiators in copper if need be, or if you think it's better. I don't want to use the old steam pipe if I can repipe. I would like to run a single loop but can run home runs if I need to or if it's better ( keep the number of pumps down for electric savings). Can probably run split loop ( 3 3/4 feeds and 1 larger return.) Want to keep it simple no special tees and such. So questions are pex or copper. 3/4 or 11/4 pipe. Can I do bottom feed and return on radiators. And loop types. Boiler size, and dhw add on.



Thanks much for all your time and effort. Deadman switching.

Comments

  • LIBob51
    LIBob51 Member Posts: 20
    You won't

    You won't see the efficiency that modcon claims to have if it's connected to baseboard.
  • JStar
    JStar Member Posts: 2,752
    Heat

    What was wrong with the steam system?
  • Jamie Hall
    Jamie Hall Member Posts: 23,170
    Why on earth

    did you get rid of the steam?  You now have a textbook example of why it is almost always cheaper and easier and more satisfactory to bring the steam system back to where it should be!



    As LiBob51 says, forget the condensing part of the mod/con.  It won't, with  baseboards (you have to run warmer). 



    I can't recommend PEX for hot water heat, although it may be satisfactory for some radiant installations.  It gets too wet noodlish.  You can repipe everything in copper, although you need to be a bit careful to allow for expansion and contraction to avoid odd noises (and, potentially, fractured joints).  I honestly doubt very much if you will get satisfactory results from a single loop, never mind that you won't be able to control various zones.  You will be happier with zoning the system using home runs and a proper manifold system.  Much happier.



    You'd have been even happier -- and a good deal richer -- had you kept the steam and brought it up to speed...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    thoughts

    I would find a guy to run the heat loss room by room for you. Then size the emitters accordingly. Guesstimate 30-35 btu per sq ft. I would not call it a well insulated house, just improved. Stil lacking vapor barrier and general construction tightness.



    Is it still a 2 family? Metering and equipment depends on this fact.



    Bottom feed and returns on rads work just fine. A home run system using pex-al-pex to a manifold is as good as it gets.
  • Joatmo2
    Joatmo2 Member Posts: 6
    Help

    Nothing wrong with steam. I have fhw base board in bsmt connected to my steam boiler. I draw of boiler water with a tempering valve so when steam is up it lowers water temp to baseboard. I've been told new steam boiler doesn't have enough internal water to continue using fhw zone. And I can't do dhw of them.
  • Joatmo2
    Joatmo2 Member Posts: 6
    edited December 2013
    Help

    Love to keep the steam. But as previously stated I have a forced hot water zone on my boiler for the finished bsmt. All I can see is a new gas boiler steam, and a new gas fhw boiler for basmt with indirect for dhw or stand looney hot water.
  • JStar
    JStar Member Posts: 2,752
    HW Loop

    Not enough water? That's a lie.



    How much baseboard is in the basement? What size steam boiler do you need?
  • Jamie Hall
    Jamie Hall Member Posts: 23,170
    I do hope

    that you haven't done anything irreversible yet.  There is no reason that I can think of that you can't have your forced hot water zone in the basement off a steam boiler -- they have plenty of water volume to do that if you wanted to do it directly off the boiler (although I'd be inclined to use a heat exchanger and go indirect).  Whoever told you that there wasn't enough water volume in a new boiler is either badly misinformed, if not untruthful (see Joe's (JStar) comment) or has no clue as to how to do steam and is trying to sell you what he thinks he can work on.  Or both.  Either way, you are going to be the loser -- probably by a factor of at least two in terms of cost.



    Find a good steam guy in the area -- there are several (check find a contractor, using the State search) and get this done right.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Joatmo2
    Joatmo2 Member Posts: 6
    edited December 2013
    Help

    50 feet baseboard in basement running on a 100 k boiler with dhw coil with 127 sq ft ci rad. Second floor same model boiler 100k +dhw coil. 127 sq ft ci rad Steam. Bsmt area 800 sq ft.



    I can join or leave separate if need be. But would like everything on one. Should be cheaper to run.



    I still think there over sized, but a mod boiler should address that. Another post averaged 30/35 btu/sq ft = 122.5k whole building. At present 127 sq ft of ci rad each floor + 50 ft baseboard in bsmt. Foot print of house is 26 x 52 exterior. 1350 sq ft.--- 31k btu total ci rad / floor. + 30 k added bsmt. Old boiler did 1 floor and bsmt.
  • JStar
    JStar Member Posts: 2,752
    Steam

    You can safely run 40 feet of baseboard with a single 100K BTUH steam boiler without affecting the steam system.



    It sounds like you need a new contractor that understands steam. Where are you located? We may know somebody nearby that can offer their expertise.
  • Joatmo2
    Joatmo2 Member Posts: 6
    edited December 2013
    Help

    Boston area, revere, just north outside of boston. Love to get him over . Originally from your area.
  • Joatmo2
    Joatmo2 Member Posts: 6
    Help

    I think I'm the closest up here not many deadmen around this area unless commercial.

    If you know anyone boston way let me know.
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