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Help-Crown Steam Boiler 20yr old leaking before season start

john_ospnj Member Posts: 11
Hi All,
New registrant, but not new to the forum - have been scouring these pages for lots of help when I moved into this old house with steam heat 5 years ago - thanks for all of that. I've put a lot of research and TLC into the steam system getting it all balanced and humming along well.
Today went to flush and clean before firing up for the season and as soon as I took off the front cover, there's obviously a leak at the front of the heat exchanger. See the pics. No water pooling underneath, just clearly dripping/drying (and onto that wiring harness). I stopped with my winter prep and am now panicking.
Specs - it's a Crown gas boiler, BSI138SNFZZPSU, dated 10/25/02. I don't think the previous owners cared for the system as well as I, boiler was well worn and signs of small leaks/corrosion where site glass meets body and other places. Piping and all else looks proper, except for near piping - it's copper. This boiler probably replaced an older oil boiler in 2002, has all the right specs except for copper material. Was really hoping to get 5-10 more years out of it before I made my discovery this morning.
The home is old 1880's, 2 floor, 1650 sq.ft. And I've calculated total EDR to 319.2. Crown chart shows this boiler of IBR sq ft at 354. So (I think) this boiler is slightly overpowered, but I can tell that 2 rads have been pulled from the system over the years. With venting all upgraded, everything balanced, home is very comfortable in the winter. So now for my questions:
1 - Is this imminent catastrophic failure!! Stop everything, pull out my max limit credit card and get someone in here ASAP?! Or is it, gently clean up around the leak, proceed with firing prep, and hope to limp through another season and deal with it in summer. Or somewhere in between?
2 - I've been happy with the Crown and have heard good reports, but now I'm feverishly looking for boilers - any recommendations on makes/models?
3 - My wet returns are 'fairly' accessible from the basement, and since they might be older than the boiler...I've read on here that it's best to replace those when replacing a boiler - agree? Any reason not to (other than costs)?
4 - Last and most speculative...so I don't have any AC in this old house, always toyed with the idea of some high-velocity system for 2nd floor (very $$)...and I've grown to really like the steam heat now and have put a lot of work into it...but any thoughts on robbing a bank and having an entire new complete forced air/central HVAC put in? Is that insane?
Any and all info much appreciated.


  • Jamie Hall
    Jamie Hall Member Posts: 22,947
    Step 1. Before you panic, are you sure the leak is from the boiler, and isn't just condensing water over the summer? It's not hard to find out: Set the boiler water level very carefully near the top of the glass, and mark it (don't depend on memory). Leave it sit for a day or two or three without firing the boiler, if you can manage that. Did the water level go down? if not, no leak. If it did? Well, loss somewhere. Now lower the water level again to below the Hartford Loop and mark it. Go away for a while. Did it hold, if not, it's not the boiler -- it's a wet return. if it did... oh dear.

    Now how serious is the leak? If it's a gallon or so a week, that's getting up there but not panic stations yet. If it's a gallon or so a day, yeah, you have a problem.

    Now in the heat pump/ducting etc. Don't, unless you want or need A/C for some reason. It won't be as comfortable, it may or may not work well on cold nights -- and it will cost a fortune. Much better to replace the boiler if need be.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • john_ospnj
    john_ospnj Member Posts: 11
    Thanks for the response Jamie. I haven't fired the boiler for the season yet.
    I'll do as you say. Although I do a wet summer layout - overfilling boiler so it doesn't sit at the normal water line through summer...and the water level right now is just at the top of the sight glass, so it has definitely gone down over the months...but probably very slowly. And I just talked to a pro and he was worrisome...said a leak down low, just over electric/burners could be trouble/do not fire up as this could expand the leak/crack and be serious trouble. Water spilling over heat-no good.
  • Jamie Hall
    Jamie Hall Member Posts: 22,947
    Panic is never a useful response. Though I've done it... do the two water level checks I suggested. If it passes, it's good for at least a while. If not, you'll know whether the problem is in the boiler or in some piping.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • mattmia2
    mattmia2 Member Posts: 9,469
    edited October 2022
    Is that currently wet? If it is someone could pull the jacket and see where it is coming from. It could be from something screwed in to the boiler rather than the heat exchanger itself.

    The copper could have pulled the sections of the boiler apart. Copper expands and contracts more than black iron and the joints are rigid. One of the reasons the near boiler piping must be black iron is that it must be arranged with some threaded joints perpendicular to the boiler connections so that as the boiler and the piping expand and contract they will turn a little bit at that joint rather than pulling the sections of the boiler apart.
  • john_ospnj
    john_ospnj Member Posts: 11
    Ok, thanks again for quick feedback. I've put water at and marked the sight glass at normal heating level per your advice - I'll watch it closely.
    I think we can cross off the wet return leak - I have easy access to all of those, inspected, and they're bone dry with no signs of water under. And based on the pics, seems a clear leak at the unit.
    And new info - a pro stopped by, one recommended on here, very knowledgeable and helpful - he said absolute leak in the seam of cast iron exchanger, just above burners, no question, needs complete replacement, right away, only option.
    I guess repairs are never an option?
    And I know we aren't supposed to discuss costs...but it was 1/3 more than I was expecting, woah...so I'm waiting on some other quotes now.
    Gonna be a lean Xmas...