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replacing the IBC boiler

gsnake
gsnake Member Posts: 5
in Gas Heating
I have an older IBC boiler VFC-15-150 which I am planning to upgrade in the near future. Can you please recommend what model I should go with? I have a 5000 sq f house (radiant heat), DWH, and swimming pool that is heated through the heat exchanger. I am also wondering if I should also upgrade my venting from 2" to 3" pipes at the same time. thanks!

Comments

  • kcopp
    kcopp Member Posts: 4,462
    edited January 2021
    How old is the VFC? Why the replacement.? It cant be 15 yrs old...
    I would install a IBC SL g3 version. Similar to the VFC in terms of pipe layout w the upgraded control...
  • gsnake
    gsnake Member Posts: 5
    it is over 15 years old. one of the first ones produced (based on the serial number). they say the heat exchanger is very solid and it does look ok so far but I am sure it will not last another 5 years :)
    I am thinking of SL g3 as well but can't decide whether I should use 114 or 160 model (114 looks less powerful than mine but does it matter that much)?
  • kcopp
    kcopp Member Posts: 4,462
    If the 115 has and does work now w/ the load on it I see no need to over size it.
    You size the boiler for the coldest day of the year... What is the coldest it gets where you are?
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,150
    You shouldn't be guessing. Do the heat calculations on your home to pin it down. You may be surprised.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    kcopp
  • gsnake
    gsnake Member Posts: 5
    kcopp said:

    If the 115 has and does work now w/ the load on it I see no need to over size it.
    You size the boiler for the coldest day of the year... What is the coldest it gets where you are?

    i have vc 15-150.. it has larger numbers than 115. this is why i was skeptical to 'downgrade'.
  • gsnake
    gsnake Member Posts: 5
    Alan (California Radiant) Forbes said:

    You shouldn't be guessing. Do the heat calculations on your home to pin it down. You may be surprised.

    Thanks.. but how to do it? Is there a formula?
    Alan (California Radiant) Forbes said:

    You shouldn't be guessing. Do the heat calculations on your home to pin it down. You may be surprised.

    kcopp said:

    If the 115 has and does work now w/ the load on it I see no need to over size it.
    You size the boiler for the coldest day of the year... What is the coldest it gets where you are?

    I am in Vancouver, BC. It barely gets to -5 C a couple of nights per year..
  • kcopp
    kcopp Member Posts: 4,462
    gsnake said:

    kcopp said:

    If the 115 has and does work now w/ the load on it I see no need to over size it.
    You size the boiler for the coldest day of the year... What is the coldest it gets where you are?

    i have vc 15-150.. it has larger numbers than 115. this is why i was skeptical to 'downgrade'.
    Sorry... I mis-read that.
    gsnake
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,150
    Here you go:
    http://www.slantfin.com/slantfin-heat-loss-calculator/
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    gsnake
  • gsnake
    gsnake Member Posts: 5
    thank you guys.

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