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Maintenance- CI chimney vent boiler vs. Condensing Boiler

Cyclist77
Cyclist77 Member Posts: 43
in Gas Heating

As I start my research forchanging out my coal stoker boiler to a modern boiler I am curious to know which type of boiler requires more maintenance?

Thanks!

Comments

  • pecmsg
    pecmsg Member Posts: 5,513

    Higher efficiency means more maintenance.

    Condensing boilers are efficient when operating below 140°F. Will your system operate below that temperature enough to justify the extra cost and maintenance?

  • Cyclist77
    Cyclist77 Member Posts: 43

    Yep, I currently have a mixing valve in the setup to bring my temperature down for radiant. I understand I would be sacrificing efficiently.

  • LRCCBJ
    LRCCBJ Member Posts: 682

    Review the comments by Steamhead on the other thread.

    Nothing more needs to be said.

  • hot_rod
    hot_rod Member Posts: 23,820

    Do you do your own maintenance on the coal stoker?

    A few tools, take an online a class on combustion analysis, watch a boiler service video from the manufacturer, and you can do your own mod con maintenance. You will possibly get a better job than having a rookie technician perform the service.

    Takes me a hour and 1/2 to break down my Lochinvar fire tube, clean, re-gasket and put the analyzer on 'er

    The computers on the mod cons tell you where to look for a fault, should one occur.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • hot_rod
    hot_rod Member Posts: 23,820

    Some number crunching would tell you more of the efficiency story. Grab the weather data for your area. Local weather stations have it , ASHRAE, NORA, etc.

    Then build a graph showing what % of the year you are at the temperature conditions.

    If you have a system that requires 180 SWT at design, first off confirm that. If the building has had any upgrades over the years that required SWT could be lower. Or it never needed 180 form day one, the installer just set the boiler at 180.

    Then using a typical outdoor reset curve, notice the # of days the SWT is 150 or lower, providing condensing temperatures for the boiler. See how many hours or days the condensing boiler actually condenses and runs in then 90% plus efficiency range.

    Screenshot 2024-12-25 at 12.01.54 PM.png
    Screenshot 2024-12-25 at 12.02.35 PM.png

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Cyclist77
    Cyclist77 Member Posts: 43

    Bob,

    Thanks for your reply. I installed and maintain my coal stoker boiler. Actually I run it all year as it has a dhw coil that I used a small circulator on a timer to supply a electric hot water tank, power turned off, and I plumbed in a mixing valve. Works great.

    I will look over the info you sent.

  • Kaos
    Kaos Member Posts: 339

    I'm sure going to get grief for this, but I've had good luck with condensing tankless units. Most are rated for combi heat (ie hot water for the house and plate HX as isolation for floor heat) and tend to be the cheapest source of heat.

    As with anything, there are many ways of doing it wrong but also not that hard to get it right. Something to watch as they do tend to be a lot of maintaince if you have hard water.

    The cost is low enough that if there is any major issues, you can simply swap it out for a new one.

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