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Combi boiler installation

beaz01 Member Posts: 3
Hi everyone, I’m turning to this site to get some advice from the pros. I’m a homeowner in the Philadelphia area. I’m converting from oil to gas and replacing my old oil boiler - hot water baseboard heat and domestic hot water hookup - with a combi boiler, also for heat and domestic hot water. I’ve had hvac contractors out for estimates, one recommended a Weil McClain wmb-120c and the other recommended the Noritz cb199. I’m having information overload reading about these two combis along with all the others on the market. Can’t find much info on the Noritz. Could you give me an objective opinion on these two and any better options you might recommend? Some details for you, we live in a 45 year old 1900 sq ft single home, one zone hot water baseboard heat with the fin type piping, 2.5 bathrooms, public water. The combi will be placed in the same place as our current boiler, in the garage right next to the chimney. Easy run for 2 pvc pipes up the chimney for intake/exhaust.

It’s two people in the household so our hot water demands are pretty low, never competing for hot water in the morning. I’m not concerned about getting the most super efficient system, anything will be more efficient than what we have now. My main objective is to get a quality system that is reliable and a reasonable price.

Any advice or opinions would be helpful. I’m looking to have this installed in the next 2 weeks. PECO already ran the gas line to our house.

Thank you in advance!


  • beaz01
    beaz01 Member Posts: 3
  • kcopp
    kcopp Member Posts: 3,830
    With 2 1/2 baths a combi boiler is prob not the best option. A properly sized unit w/ an indirect water heater off the boiler as a separate zone is a better option.
    I have not installed that weil mclain model. It is a re-branded Ferrolli from Italy. Not a great track record over there.
    Noritz makes good tankless water heaters but not a lot of service history in the boiler market.
    Don't rush the decision.
    Find a good installer to help you through the process.
    Make sure they know the boiler VERY well.

  • DZoro
    DZoro Member Posts: 1,048
    Not really familiar with either of those, have done service on the Noritz, but am not a fan of either. Any contractors suggest Lochinvar Noble?
  • beaz01
    beaz01 Member Posts: 3
    Thanks for the input. Neither of the contractors mentioned Lochinvar Noble. It seems like they have their preferred manufacturer and build the case that they’re the way to go. That’s why I came to this board to get some objective opinions. The summer/winter hookup we presently have with our current boiler has been fine for the two of us for the last 15 years so because of the space available for our new gas boiler I was looking at combi units. I suppose I’d consider other types of boilers that’ll fit the footprint we’re using now, approx 3’ x 3’

    Are there boiler brands that you’d recommend based on reliability and performance any brands you’d stay away from?

    Thanks for your help. Trying to learn as I go here. I want to make the best informed decision possible.
  • kcopp
    kcopp Member Posts: 3,830
    I am a big fan of the IBC units. Installed about 30 of them and had very good results.
    12 parts inside and only 4 moving parts... less to go wrong.