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Lochinvar boiler question

frgeohafe
frgeohafe Member Posts: 1
edited March 2017 in Gas Heating
I am responsible for a church-run school which is currently heated by five 1997 Weil-McLain EGH series gas boilers, totaling 2,000,000 BTU, all controlled by a Tekmar 258 (it's a hydronic system; we've never seen more than three boilers running at a time). Two of them have cracked blocks and have been shut down; a third was rebuilt with a new block last fall; and the remaining two are probably not long for this world. Our mechanical contractor (whom I trust, and has a stellar reputation in the industry) is proposing keeping the one newly-rebuilt unit and installing three Lochinvar CBN 399 boilers. Does anyone have experience with Lochinvar, and with this particular line? I've read up on their products and have seen some mixed reviews, but those assessments seem more concerned with residential applications.

Thank you.

Comments

  • Steve Minnich
    Steve Minnich Member Posts: 2,674
    Its said over and over here about how necessary a heat loss load calculation is. It looks like you'd be keeping the same amount of btu capacity with the 3 new boilers and the rebuilt boiler. Was a load calc performed? The picture by my name is 2 Lochinvar KHN 199's we installed in a church that had almost 600,000 btus from their old boiler. Obviously, it was way oversized. So, the load calculation is a necessity and is Step 1. The KHN is a modulating condensing boiler and there were times when only one boiler was firing at 20% this past winter.

    In a good, better, best scenario I would put the CBN in the "okay" category. There are better choices in terms of efficiency and control. If it were me, I'd opt for a cast iron boiler over copper boiler any day. It will give the same efficiency and last forever. That would be a "good" choice. The KHN or FTXL would be a "best" choice.

    Its only my .02.

    Steve Minnich
    Minnich Hydronic Consulting & Design, LLC
    [email protected]
    Ironman
  • Zman
    Zman Member Posts: 6,985
    edited March 2017
    The CBN is an atmospheric copper fin tube boiler. There are probably a dozen companies making similar boilers. They are practically a commodity.

    I agree with Steve that more research is needed. 20 years is a relatively short life span for your existing cast iron boilers. I would dig into what led to their failure. They may have been oversized and short cycled themselves to death.Perhaps they where victims of water quality issues or thermal shock.

    Many times boiler plants are designed by folks who focus too heavily on design day conditions and use generous safety factors.
    Systems like this end up not functioning very well on the typical day.

    Tell us more about the type of emitters these boilers serve?

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,510
    edited March 2017
    With multiple boilers, you could have the option of automatically firing one to all, one by one, depending on the outside temperature. In addition, you may be able to take advantage of outdoor reset to vary the water loop temperature with the outside temperature.
    If the boiler has really cracked, then I would pay attention to the piping, or water quality which has allowed this to happen, (thermal shock?). I would expect a lifespan of 30++ years, if regular maintenance is performed. The real key is the installer, and the quality of his design, and installation. He should study this as if it were a new installation, and verify the output of the emitters, and radiators in all areas.
    A fairly accurate, and free heat loss program is the SlantFin app for IPad, and android tablets.--NBC