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Boiler Efficiency

I am working on a bid and need a steam boiler with an AFUE of 83% or higher. One option for 60-75k btu input the other for 76-140k. Any suggestions? I'm not having much luck and there is no option to simply say "one isn't made". Thanks in advance.


  • Rod
    Rod Posts: 2,067
    Burner Type

    Oil or gas ?
  • Hovlandstech
    Hovlandstech Member Posts: 22

    Natural Gas
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    More details needed

    Can you give us more details about the project and it's requirements?--nbc
  • Hovlandstech
    Hovlandstech Member Posts: 22
    Found one

    I've found one that meets the requirements in the smaller sizing. Now I just need one that reaches the efficiency and is between 76 and 140k btu input
  • Hovlandstech
    Hovlandstech Member Posts: 22
    Want to keep it limited

    I don't know if any competition is lurking. For a local state administered low income weatherization program. Bid requirements are that all line items must be complete to constitute a responsible bid. One line item is for steam boiler 83% efficiency in each of the sizing categories. I would love nothing more to be the only one able to find such a creature.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576

    Just use the term "down-fired" in your proposal--NBC
  • Rod
    Rod Posts: 2,067
    Boiler Efficency

    Hi- You may have a problem finding a boiler with an AFUE rating of 83 in gas. Some come close 82.5.  Burnham, Peerless, and Smith all have boilers that come close.  The AFUE rating is given for the base model but you might want to check with the manufacturer as using a spark ignition usually adds a point to the efficiency over a standing pilot.

       A lot of the pros feel that if you use a wet based oil boiler with a gas power burner, that the efficiency is around 86 but unfortunately this probably isn't documented. You might check with Smith (G8 model ) and Slantfin (Intrepid model) as these are wet based boilers offered with an option gas power burner, to see if they have any documentation on the AFUE efficiency for these setups.

    - Rod

  • icesailor
    icesailor Member Posts: 7,265
    Steam Boiler Efficiencies:

    Am I wrong in saying that the boiler must be sized to the installed radiation on a steam system? That a 75K boiler may not have enough "nuts" to fill the system with steam?

    If you know what you are doing with designing and installing a steam system and what goes along with it, overwhelm them with facts that the low bid hackaroos don't know about. Often, if you are the only one with the true facts, you get the job because you are obviously the one who knows what's up.

    A lot of the problems I see here is because the higher bidder didn't set out what they were doing and why. And some hack throws a bid in that won't cover the needs of the job. They get the job, the customer has a problem, and you didn't get the job. But you may get the chance to fix it.

    And steam systems seem to be the #1 problem.
  • Hovlandstech
    Hovlandstech Member Posts: 22

    This is a 100% low bid contract. They don't have any specific jobs planned so I can't play the sizing card. They get pricing up front on everything from a steam boiler install to water heater install to furnace clean and tune and estimate how many jobs they will do over the course of the year. Whoever ends up with the lowest total bid price that meets their requirements gets the work. These are state provided documents and specifications. I'm guessing that guys have always provided a number and nobody looked too deep into the efficiency. I think I've found a mistake in their document and would like to use it to my advantage.
  • Paul48
    Paul48 Member Posts: 4,469

    series 8, 3 section w/ carlin ez-gas now offered by the manufacturer.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Insane requirements.

    I am not a heating contractor, but at one time I worked for a small electronics defense contractor. We got an RFP for a system that was very badly done, if its objective had been to purchase equipment for the stated purpose. But they also specified how it was to be done, and what some of the components were.

    One of those components had the exact description copied out of the catalog of a manufacturer. That device would do what was wanted. But some moron in the government added one line to that description that made it impossible to do the job because no manufacturer made one that way, and if one did, it would not have worked at all.

    While we needed the money for that job, we had to no-bid it because we knew we would have had to forfeit the required performance bond when it was found not to work. We later found out no one bid on that RFP. Governments are like that. An RFP should specify what is wanted but not how to do it. Government agencies often failed that way in those days (mid 1960s).. I would like to think they had learned their lesson by now, but apparently not.

    (RFP is request for proposal.)
  • kcopp
    kcopp Member Posts: 4,395
    Smith G-8 has been...

    around awhile w/ the Carlin EZ gas. Depending on the size you may be able to squeak by w/ a Weil ER gas steamer... its like 82.9 to 83% afue.... spark ignition and flue damper.
  • Paul48
    Paul48 Member Posts: 4,469

    claims 85+ for steam.
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,849
    Does it say "83.0%"?

    Or "83%"?

    82.9% = 83% to the nearest percent.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
This discussion has been closed.