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Dew point & altitude

Tim Potter
Tim Potter Member Posts: 273
I was reading the “How to obtain the highest amount of condensing!” post
& the corresponding PDF: http://www.fcxalaska.com/PDFs/AshraeCondensingTechnology.pdf
& it got me thinking.

I have an injection mixed, in-floor radiant heating system with a cast iron boiler installed at 9000+ elevation in Colorado. I use the ESBE Thermic valve & 140* element to control return water temps to the boiler.

After reading the post & the PDF, page 40 stood out for me. It shows the condensing temps are lowered from 135* to the 120 - 122*range at 9000’.

My question is: would I see an small increase in efficiency (I realize its not a condensing boiler) by changing the thermostat element from 140* to 122* or would the efficiency stay the same but just lower the supply water temps to the injection system?

Thank You:

Winter Park, CO & Arvada, CO


  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    I am not clear on what you are asking? Is this a condensing boiler?
  • I believe this in regard to a cast iron boiler, so the condensing may be the kiss of death, due to rusting on the sections.
    There are other possibilities for saving ful, however.--NBC
  • KC_Jones
    KC_Jones Member Posts: 5,692
    I think what is being asked is since at their altitude condensing needs a lower temperature, could the cast iron boiler be turned down lower and NOT condense. I don't know the answer, but that is my interpretation.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Zman
    Zman Member Posts: 7,542
    I am following your thinking,
    I would be careful of playing with the lower end of that one.
    If your vent is not in a conditioned space, your boiler may not condense, but the flue sure will. I have seen quite a few rot out when the boiler is set that low or is short cycling.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Tim Potter
    Tim Potter Member Posts: 273
    Thank You all for the input.

    Zman, The boiler is in the conditioned space, & I do have a boiler buddy, so cycle times are long.

    NBC, you summed it up, just pondering "how low can you go"

    For the first 15 years of its life, this boiler always condensed being it was directly connected to the infloor radiant. I added the injection & Boiler Buddy
    Winter Park, CO & Arvada, CO