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Questions from a newbie on replacing steam boiler

Hello, and thanks in advance.

In preparation for winter I recently had a professional in to tune-up our existing single-pipe steam boiler, which is 25+ years old. He immediately said that we needed to replace it because of unacceptable CO output (he also pointed to several sooty areas that he said should not be there). We called a second professional for his opinion and he concurred.

Both men suggested we replace the boiler with the Burnham IN4.

As a complete novice, it's hard for me to evaluate their recommendation, or to know what the right questions are to ask (it's an expensive project that I want to get it right). In particular, I'm interested in efficiency; are there alternative steam boilers that are more efficient that the Burnham? Alternative setups or conversions that will save fuel over the long run? I know that all of this depends on the specifics of my house and setup (which I'm happy to share if it's helpful), but any general thoughts or perspectives would be super useful.
Thank you!


  • mark schofield
    mark schofield Member Posts: 152
    You might want to check out find a contractor in your area. The steam guys on this site are awesome. Possibly someone in your area who does steam could give you some advice.
  • lchmb
    lchmb Member Posts: 2,997
    Where are you located? Never hurts to get estimates and request they explain how they sized it and guarantee that it will be piped per manufacturer specs...
  • Not a fan of the IN for steam, for what it's worth.
    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    Paul S_3
  • MilanD
    MilanD Member Posts: 1,160
    Call me crazy, but can't CO levels be adjusted by correcting burner nozzle, pressure, etc (I'm assuming this is oil?)... Also, if the thing is backdrafting CO, new boiler won't change obstruction in the chimney or low draft conditions that all may also require possibly having to reline the chase? There are many unscrupulous "contractors" out there who would rather make a sale then spend time tuning up what's there, for obvious reasons.

    What is your current boiler? Fuel? Can you post some pics? How did they arrive at CO levels? Do you have a printout of their readings? Is the boiler otherwise working? What prompted you to think about replacing it?

    Sorry, I'd like to believe the techs "out there", but not all guys out there are the guys who contribute here. My experience with forced air guys here in Cincinnati and stuff we see here on the wall tells me to trust, but verify. Call the 3rd and 4th person for an opinion.

    Anyhow, pics will help.
  • Fred
    Fred Member Posts: 8,541
    Did either of the guys that showed up ever clean the boiler and do a combustion analysis? Sounds to me like the very first thing to do is make sure the burner is properly adjusted. Boiler typically need to be replaced because they leak water, most other things can usually be repaired/adjusted. Were the guys you called out steam pros? Where are you located. One of the Pros on this site will give you an honest evaluation. In all probability, you won't get a new boiler that gives you enough efficiency savings to pay for the change out before it needs to be replaced, unless the current one is way over sized and even then it might be questionable. My steam boiler, a Burnham, is 34 years old and I will not replace it until it dies from a drowning.
  • j a_2
    j a_2 Member Posts: 1,801
    I'll assume it's gas due to they recommend the Burnham IN4..unless they want to convert you from oil to gas...

    1. How did they arrive at the size of replacement
    2. What steps did they take to test existing boiler, draft check,make up air, existing conditions,chimney intact..gas pressure, static and dynamic...
    3. How often have you serviced existing boiler
    4. Burnham gas boilers are fine, parts are readily available, it's a fairly simple boiler ..
    5. How did they test the c o...ambiant or in the venting of the boiler
    6. Do you have an existing c o alarm
    7. Your savings will come from a properly sized and piped boiler..along with vents sized and adjusted correctly...

    Good luck
    EBEBRATT-Ed Member Posts: 13,800
    If the boiler is not leaking and the efficiency is decent and it heats well keep it until it dies.

    As far as the bad Co readings that can be fixed by someone that knows how. Does not mean the boiler is bad. May just need a good cleaning and adjustment by someone that knows how

    It's possible on a cold start they didn't run it long enough.

    A pot of water on a gas stove will make CO until the pot gets hot
  • ruster
    ruster Member Posts: 3
    Wow, thanks everyone for the thoughts. And yes, it's a gas boiler. The first guy took some measurements with a device, though I wasn't there at the time (wife was). I don't think he ran it very long. We can't find the full printout he produced, though we do have these numbers...
    • CO2max: 11.9%
    • Fluegas temp: 191.4 F
    • O2: 14.0%
    • CO: 279 PPM
    • qA: 6.9% (?)
    • undiluted CO: 760 PPM
    We do of course have CO detectors throughout the house, though they're of the normal variety. We're also expecting a baby soon (very soon), and babies are apparently more easily affected by low levels of CO.

    Pictures of the boiler below.

    These are the problematic scorched areas:

    Thoughts? I understand that the important bit is all in the plumbing, but as an outsider it's pretty hard to judge whether someone is going to do it right. Should I seek more opinions from local professionals? I'm in the Boston area.
  • Fred
    Fred Member Posts: 8,541
    Go to the "Main Site" tab at the top of the page a click on "Find a Contractor" enter your zip code and see who come up. I think some of the Pros here do service the Boston Area. Does the boiler flue pipe vent into a masonry chimney? Has anyone looked at the chimney to see if it is okay? I would say this issue can be fixed without replacing the boiler but regardless, new boiler or current one, if the chimney is the problem, that should be where your money is spent. Fluegas temp seems low to me but one of the Pros here can speak to that.
    HVACNUT Member Posts: 5,255
    Those readings are off. He either took the readings in the smoke pipe, north of the draft hood, or he didn't keep the probe in long enough for the boiler to reach steady state.

    Looks like there's some rollout at the burners.

    Needs a good cleaning. Brush and vac the flue passages. Remove and clean the burners and tray. Check the chimney base. Check/clean the orifices. Check lockup and manifold pressures.
    Perform a "real" combustion analysis, and make adjustments as necessary.
    Install a rollout switch.
    Recommend a spill switch if one is not already present at the draft hood.

    Like @Fred said, find a contractor above. You'll be happy you did. He/she will also go over the whole system, checking the LWCO, pressurtrol, vents, etc., to make sure it runs safe and sound.
  • AMservices
    AMservices Member Posts: 605
    I'm betting you have a dirty heat exchanger.
    If the heat exchanger is dirty, the flue gases can't pass through the boiler the way it's supposed to and the flames can start to role out the front.
    How does a gas burning appliance become dirty?
    It can happen if the boiler is running and there's a lot of dust in the air, via someone sweeping or construction taking place around it.
    The burner is drawing air in from around the basement, so when there's dust floating around, it too is burned and can get trapped on the heat exchanger, restricting the air flow it need for good combustion.
    Another possibility could be not enough combustion air in the basement.
    If there's not enough air for the amount of gas your burning, you could be burning to rich and that too can cause a carbon build up on your heat exchanger.
    You can have a heating technician confirm this by taking the flue pipe off and trying to look through the flue passages in the heat exchanger. You could have it cleaned, but unfortunately it's usually a bandaid for what will be an on going problem.
    Once a boiler starts getting a carbon build up, it's very hard to get clean enough to have it running like new.
    My opinion, start getting prices.
    A new boiler has more safeties and better design for efficiency.
    When a steam boiler is properly sized and piped by a steam pro, it can be just as efficient, give you as much control, is considered by many to be more comfortable and heat your home for many more years, with much less costly problems that you can have with something else heating your home.

    j a_2HVACNUT
  • j a_2
    j a_2 Member Posts: 1,801
    Above comment is a very sensible one...try flooding the boiler and check for water leakage..if it leaks its pretty much given you the answer...The guys that came b4 shyed away due to a liability thing...flame roll out caused by dirty passages is lack of service...there afraid to clean them because it will often lead to disturbing enough rust and stuff to cause a leak....
  • j a_2
    j a_2 Member Posts: 1,801
    Last year mass offered a early boiler replacement rebate. Of approx 1800 for your situation....30. Plus
  • Steamhead
    Steamhead Member Posts: 16,256
    I'll bet the chimney is blocked, as others have said- that would reduce the air supply to the burners, causing soot. Or, the gas pressure in the manifold is way too high. Either way, you probably don't need a new boiler.

    And I'll second using Find a Contractor. Where are you located?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • BobC
    BobC Member Posts: 5,410
    Those numbers don't make a lot of sense, I suspect the reading was either taken at the wrong spot or much to early in the combustion cycle.

    The answers above are from knowledgeable pros who have worked on these things forever, i would take their recommendations seriously.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,254
    Don't forget about combustion air requirements (especially because I see 2 appliances going into the chimney).
    BTW Wallies, what's this? (circled in red)
  • AMservices
    AMservices Member Posts: 605

    Don't forget about combustion air requirements (especially because I see 2 appliances going into the chimney).
    BTW Wallies, what's this? (circled in red)

    That's the boilers pressure gauge
  • ruster
    ruster Member Posts: 3
    Ok, this has all been helpful. Thank you. I'll seek a third opinion (and hopefully a more rigorous combustion analysis), and will post back here when it's done. Looks like there are a few guys working in my general area (found via "Find a Contractor").
  • j a_2
    j a_2 Member Posts: 1,801
    It is a gauge. But I see how you thought it was attached to the valve at water heater
  • j a_2
    j a_2 Member Posts: 1,801
    Yup boiler looks a little undernourished....and it will fire back at you...once again a c o detector in basement area and outside each bedroom group...in the bedroom then its way to late....I am sure you know that, but they are very easy to overlook ....
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,254
    j a said:

    It is a gauge. But I see how you thought it was attached to the valve at water heater

    Yup...I thought it was on the inlet of the WH gas valve...time for a bigger monitor...lol...thanks!.