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commercial mod/con

Uni R_2
Uni R_2 Member Posts: 589


  • bigwilly104
    bigwilly104 Member Posts: 50
    Commercial mod/con

    I need to quote to replace a commercial boiler. I want to give the option of a mod/con. I was thinking the Laars rheos+. I need about 1.2 million BTU. I have never seen any mod/cons this big so I cant make a decision bassed on experiance. I thought about a bunch of Knights running parallel but thats got to cost alot more. Also the parts cost from Lochinvar is just crazy I dont want to sell a golden egg.
  • tim smith
    tim smith Member Posts: 2,752
    Re: commercial condensing boiler

    I laid out a job w/ a client just lately, same load required. I did not do install due to time but the co. who put it in used what I spec'd. 3- Triangle tube Prestige boilers sequenced and staged. I think you would find them to be moderately close to a single large mod/con. JMHO, Tim
  • Brad White
    Brad White Member Posts: 2,398
    Commercial Mod Cons

    Hydrotherm KN's come in 600 MBH, 1000 MBH and 2000 MBH inputs and are forgiving of low gas pressure.

    Multiples of other smaller boilers would work as well and with staging controls offer advantages of low-load modulation and back-up.

    There are plenty of larger commercial ModCon boilers these days, from Viessmann (Vitocrossal), Buderus, Aerco and others which may be even too large for your needs.

    There are choices. This is good.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • tim smith
    tim smith Member Posts: 2,752
    KN boilers?

    Brad, I still wonder about the cast iron design of the KN boiler. I like the general concept of this boiler except for what I consider to be sacrificial cast iron at the lower section of the block of this boiler. Just a ?? Tim
  • Brad White
    Brad White Member Posts: 2,398
    We had the same reservations about that, Tim

    We all said, "Cast Iron? Condensing?". We sat down with Ken Cohen, the boiler designer.

    Looking over the casting geometry (small castings with stress points well distributed), the downward flow of flue gasses and condensate (brushes the condensate down so there is little re-evaporation which causes salt build-up and corrosion) and the thickness of the material, convinced us that this boiler had an application.

    The material thickness was extrapolated over a 30 year lifespan (sacrificial as you noted) and the material would still be within ASME specifications for a boiler.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • Joannie_14
    Joannie_14 Member Posts: 22

    If you have any questions about the Rheos+, feel free to give us a call here at Laars. 603-335-6300 and ask for Applications Engineering. Paul, Bill and I can help.


    Laars Heating Systems
  • hot_rod
    hot_rod Member Posts: 22,158
    what about the loads?

    if you have varying loads that Aerco Modulex model modulates from 45,000 to 1 million a 23 to 1 turndown!. Quite a turn down for a large boiler.

    I saw those boilers used in an apartment building in Italy, under another name. It had quite a few seasons under it's belt and the property manager was impressed with it's performance and fuel use.

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • large modcon

    Before you blow off the Knights, suggest you price the total job. The Knights built-in internal sequencer will save you a lot and simplify the job. And you'll love the easy install.
  • Rocky_3
    Rocky_3 Member Posts: 232
    Put in two Buderus

    I put in two Buderus SB 615 series mod/cons at a hotel. They had Riello burners. Really sweet set-up. Each boiler was 1.8 million, but they have several smaller sizes to choose from.
    Warm regards from chilly Fairbanks,
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