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Feedback on Proposed Repairs

JStar
JStar Member Posts: 2,752
5 year old 112MBTUH Steam Boiler. When it's fully fired up, the house sounds like a percussive orchestra. Bangs, whistles, sloshes, the works. Some of the 2nd floor radiators are panting like a dog. I find that the original piping is a bit off. The main bullheads into a tee and splits off in two straight lines. So, one side is pitched properly, the other not. The basement ceiling is barely 6ft. There is not enough height to repitch the main. I proposed converting it to a counterflow main. Rearrange the bullheaded tee and keep the properly pitched main untouched.



I draw up an estimate, head out to my next call, and then of course, I start doing my best thinking. The main is 2" with 4 1" take-offs. The whole system only has 6 radiators, all piped 1". Damn. This boiler has to be oversized. I get a chance to revisit the house. Measure up all of the radiators, add a generous 33%, and calculate a required input of 80MBTUH. So, it is oversized. By about 30,000. Great.



Now, I'm not so sure that the piping repairs are going to solve everything. They should still be done, but I don't want to be in the situation of being married to the system after making promises. So, what I'm looking for feedback on, mostly, is the predicted success of converting the main to counterflow. The connected radiation on the main is (If I remember correctly) 125 sq.ft. I'll be able to pitch it 2" over 10 ft. back to the boiler.



The sizing issue...well, that's being discussed by the higher-ups.

Comments

  • Steamhead
    Steamhead Member Posts: 15,349
    You need at least twice the pitch

    on counterflow as on parallel-flow- 1 inch in 10 feet vs. 1 inch in 20 feet. So with a low ceiling like that, parallel-flow is the best way as the main won't hang so low.



    Also with parallel-flow, the effect of an oversized boiler won't be as bad since it won't be fighting the returning condensate.



    How about some pics?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • JStar
    JStar Member Posts: 2,752
    edited November 2011
    RE

    Sorry, no pictures at this time.



    If I keep the main parallel-flow, the dry return would be about 24" above the water line when it's all redone.
  • Steamhead
    Steamhead Member Posts: 15,349
    Any way

    to switch to a wet return?



    If not, you can probably get away with a 24" "A" Dimension. We shoot for 28", but I've seen systems work fine with 18" if the pressure is kept low.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • JStar
    JStar Member Posts: 2,752
    RE

    No way to make a wet return. I was thinking the 24" A-Dimension wouldn't be the end of the world. I was concerned about it because of the oversizing issue. I suppose that the labor involved in converting to counterflow, or fixing the parallel-flow is just about the same. Would make sense to keep it parallel to help the condensate.
  • JStar
    JStar Member Posts: 2,752
    edited November 2011
    RE

    Just remembered. The other part that bothered me about keeping it parallel-flow. The radiator run-outs are horizontal off the main for about 8 inches. And they are all grouped near the end of the main. I didn't want the condensate to slosh around near the end elbow and create problems in the run-outs. 
  • Steamhead
    Steamhead Member Posts: 15,349
    Shouldn't be a problem

    as long as the water can drain into the return without backing up. 
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • JStar
    JStar Member Posts: 2,752
    RE

    Thanks for the input. Sounds like we have a better plan now.
This discussion has been closed.