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How much near-boiler piping can be re-used?

In the off-season, we plan to replace a leaking 19-year old gas-fired Weil McLain EG-75 with a new boiler (not sure which one, but will be sized smaller to match EDR) and I have some questions:

1. When the new boiler gets hooked up, can my existing near-boiler piping be re-used to some extent? The boiler is in a deep well in the floor so there's plenty of room to adjust height up and down and back and forth

2. Is my current piping done right? I have 2" risers going into a 3" header, but then the take-off to the mains is in the middle of the header between the two riser connections. I understand from Dan's book that this is not ideal. Also there's just that one take-off from the header that then splits into two mains. Is this OK since the mains ultimately make one big loop and join on the far end of the basement where they dump into one return?

The mains are 2.5" and we have a pretty quiet system--no hammering--just the odd clank from a radiator when things are first heating up or as they cool down.
Slant/Fin TR-40 w Carlin EZ-Gas burner. 3" riser into 3" drop header. Two 2.5" mains: 43' and 25' serving 11 radiators w/ EDR of 585. 3200 sq ft 1850s Greek Revival house in Concord NH - 7478 avg degree days.


  • ChrisJ
    ChrisJ Member Posts: 15,768
    edited March 2014

    Just a homeowner here, but none of that piping can be re-used.

    You cannot pull steam from the header in between the boiler risers, this causes water to backup.  Next each main should pull steam from the header directly.

    For example : http://www.comfort-calc.net/Steam%20Piping/Steam_boiler_piping.JPG

    Here is an excellent video explaining things better than I can : http://youtu.be/6BCCXW8lA1g
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • KC_Jones
    KC_Jones Member Posts: 5,741
    Homeowner as well

    I have a different perspective on your question.  If you are asking if the configuration can be reused I would say no, it's not really ideal.  If you are asking if fittings can be reused individually I would say as long as you can get them apart in good condition it shouldn't be a problem.  It all depends how much work versus how much money.  I am doing a replacement also when the weather warms up and I am going to attempt to reuse some fittings...I will repeat that ATTEMPT to reuse some fittings.  It all depends on how they come apart!  I think I saw Ward on the side of one of those elbows, if you indeed have Ward fittings those should be US and of a good quality so could be reusable.  Just my $0.02 worth.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Fred
    Fred Member Posts: 8,542
    edited March 2014
    Maybe the Dead Men knew something?

    Guys, maybe the dead men knew something we don't quite understand?? I have probably one of the quietest one pipe systems I know of. I have to add little to no water, except for blow downs and the steam is good and dry and  it runs on just a few ounces of pressure. (I'm knocking on wood the whole time I'm writing this). It has taken me a long time to get the system to this point. The thing is, the entire system is original (112 years old, 15 radiators, 5000 sq. ft. house), except for the boiler, which is a 31 year old Burnham series 4B and the vents, naturally.Both of my mains run off of the center of the header, between the risers, again as originally plumbed and there is not one bit of problem. I'm not sure what the trick is but it works. I will say the bottom of the header is 40 inches above the water line. That may be part of the trick.

    If/when I need to replace the boiler, I am sure I will redo the header to probably do a drop header and put the mains towards the end of the header, before the equalizer but who knows, I may be dead before I face that task.

    Looking at these pictures, I'd probably swing that right riser to the left, turn that Tee going to the main 90 degrees and tie the riser into that, then I'd take the Tee that the riser is currently tied to and turn it up and tie my main into it. Preferably I'd try to work another Tee into the header at that end and separate the mains so they both drop, independently to the header. That's what I'd try.