Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

IBC VFC 15-150 Modulating boiler with 10:1 ratio

DrPcFix Member Posts: 7
I'm looking to install an IBC VFC 15-150 in my 5500 sq ft home in Long Island. Heat loss comes in at 90K for the home. However, with 6+ members drawing down an indirect HW tank (120 gal or so) for showering I feel that the added capacity of the VFC will help keep up with the HW demand and the 10:1 modulation will still allow for efficient heating.

Any thoughts?

Also, considering the water quality issues in Long Island, am I better of with a SS tank or perhaps a stone lined or even glass lined tank?

Suggestions welcome.


  • kcopp
    kcopp Member Posts: 4,305
    edited March 2017
    The VFC is a top of the line unit.
    What do you have for HW in your home now?
    I cant think a 119 gal indirect couldn't keep up.
    IBC actually makes a SS indirect that is made from 444 Stainless and is passivated. I am told it is very sturdy.
  • DrPcFix
    DrPcFix Member Posts: 7
    edited March 2017

    Even IBC, with the very high quality 444 Stainless has no confidence that the tank will survive chlorides above 80 ppm and specifically excludes that from their generous 10 year warranty.

    So, like every other manufacturer who touts the ongoing benefits of their SS tanks, the warranty is effectively worthless unless you can prove, beyond a reasonable doubt, that the chloride level is below their requirements.

    I say............let them all sit and collect dust. Use the glass lined tank and change the anode. It will probably outlast the SS tanks at reduced cost.

    Our latest water quality report shows chlorides ranging between 11 and 60 ppm and IMHO a tank should last way longer than 10 years -- especially considering the high cost.
  • kcopp
    kcopp Member Posts: 4,305
    Another option would be to use one of these. They are stainless AND they have an anode rod.

  • Paul Pollets
    Paul Pollets Member Posts: 3,649
    Maybe it's less expensive to treat the water and remove the chlorides?
  • bob eck
    bob eck Member Posts: 930
    How about a 70 gallon Vaughn stone lined indirect water heater going into a Vaughn 80 or 120 gallon stone lined electric water heater? The elements in the electric water heater will keep the 80 or 120 gallons stored all at 125 degrees or 130 degrees.
    Reduce the kids and guest shower heads from 2.5 GPM to 1.5 GPM and this can reduce your GPM of hot water needed big time.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited March 2017
    You can't oversize a condensing boiler on the high end of the modulation rate. Boiler will never go there. It's basically parked with the engine off until it's called upon.

    With that said, I'd pay the little extra for a Viessmann Vitocell 300 EVI-120, as it has a clean out so it can be serviced and your range of chlorides wouldn't be an issue. Most of the other mfgs, do not have a clean out in them to service the tank.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."