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Navien combi boiler systems

I currently have a 32 year old peerless boiler Beckett burner oil fired system with an electric water tank and I’m interested in replacing it with a new system. The Navien Combi boiler fired by liquid propane was highly recommended to me as an energy efficient system, however I read some concerning reviews about the true efficiency of the system and its durability and difficulty getting replacement parts. I’m not sure if I should stick with an oil fired system similar to the one I have or venture out and try one of these energy efficient systems. Any help or advice would be greatly appreciated. 


  • kcopp
    kcopp Member Posts: 4,386
    If your only other option is LP I would stick with oil. A good 3 pass oil fired boiler would be my choice.
    Pure pro Trio, Biasi, pensotti, buderus.
    EBEBRATT-Ed Member Posts: 15,300

    The debate continues about CI boiler versus Mod Cons. There are some good mod cons but I wouldn't include Navien on the good list

    The short version:

    MOD CON more $$$
    More efficient (in some cases depending on your system)
    Shorter life span maybe 15 years
    Sometimes you have to wait for parts
    parts are $$$ and are perpriotery you have to go to the boiler mfg
    Not everyone can work on them

    CI boilers
    less $$$
    Should last longer....your 32 year old boiler is a good example
    parts are more generic, it would be rare not to be able to fix up a 30 year old boiler
    parts are less $$
    The average service tech "should" be able to service it

    I will stay out of the oil versus propane debate except
    getting rid of the oil tank can be a bonus if your going to sell the house

    Oil is 140,000 btus/gallon
    Propane is 91,500/gallon

    Efficiency wise CI boiler will be in the 82-83% range on either fuel

    A mod con (even though they are advertised at 95%) will only do 95% if connected to a low temp radiant system

    With baseboard HW they are probably 88% if you have CI radiators they may be around 90%

    Whatever you decide the quality of the installer is most important

    We see horror stories here every day

  • SuperTech
    SuperTech Member Posts: 2,119
    Anything but a Navien....getting parts for them isn't a problem actually.  Reliability and quality of the boiler itself is.  I would stick with oil myself and replace the boiler with an Energy Kinetics or three pass cast iron myself. Quality of the installation is the most important thing with any boiler. 
  • Daveinscranton
    Daveinscranton Member Posts: 148
    In the early days of computerization of road racing motorcycles, Eraldo Ferraci, a great builder, pointed to a black box, padded and insulated, stuck under the seat and between 2 upswept exhaust pipes and said: “ No one in there is happy!”  He was referring to all of the sensitive electronic parts.  I think of that when I look at a mod con.  Any mod con.  Every time I look at a mod con.  Including my own.

    Now, I like mod cons.  The science is elegant. Takes awhile to dial one in.  After you select and pipe it.  And a bad installation is real trouble.

    I personally would go with a cast iron boiler and efficiency in the low to mid 80% range if I had to use water temperatures that (largely) put a mod con out of condensing range.  

    I don’t like the idea of (still) sensitive electronics and electrical parts subjected to all those heat cycles.  As a disclaimer, I am not a pro.  Always been a science geek. And took a lot of thermodynamics courses.  

    Best wishes