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Need help choosing a new Mod Con gas fired boiler

Chevy57 Member Posts: 8
I need help making a decision on brand of boiler. I was hearing all great things about the Bosch boilers and thought I had made a decision on the ZBR 28-3 but then I read that they are aluminum heat exchangers which is what is failing on my old dunkirk after 18 years. So why is a bosch aluminum, heat exchanger ok and Dunkirk not ok? This sent me down a rabbit hole and I found Navien boilers. Available locally in stock. similar price point to Bosch. They advertise a very impressive turn down ratio and have stainless steel fire tube heat exchangers. Stainless sounds good, fire tube technology has been around since early 1800s so probably apples to oranges to compare Bosch and Navien. Navien seems to have a great reputation for on demand water heaters but I'm not looking for a combi unit as I have a side arm. Help I'm way overthinking this.


  • Hot_water_fan
    Hot_water_fan Member Posts: 1,838
    Ha! Plenty of people here would be happy with a modcon lasting 18 years, they'd claim that'd never happen. All depends on your perspective I suppose.
  • Chevy57
    Chevy57 Member Posts: 8
    hot water fan,
    I agree. no complaints from me it owes me nothing. I would buy the exact same make and model but it was discontinued 2 years ago and I can't find any.
  • GGross
    GGross Member Posts: 1,040
    Here are the brands I would be comfortable having in my own home.
    Viessmann, Triangle Tube (instinct or prestige), IBC(sl or vx), Lochinvar

    The most important thing is to choose a qualified installer that you want to work with, you install the brand they recommend and deal with the most.
  • hot_rod
    hot_rod Member Posts: 22,107
    I think water quality has a lot to do with HX life. Treat the water to the manufacturers spec, or better.

    Combustion adjusting also, every time it is serviced.

    This assumes it is piped and pumped appropriately also. Lochinvar has been my best performing and long lasting brand. I like the control features on the Knights.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • GroundUp
    GroundUp Member Posts: 1,905
    X3 on the Lochinvar products. The fit and finish isn't the best (door clips are kind of janky, etc) but the controls and accessibility easily make up for that in my opinion. IBC would be my next choice, then NTI or Burnham tied for 3rd. TT and Viessmann tied for 4th. Navien at or near the bottom.
  • kcopp
    kcopp Member Posts: 4,431
    I really like IBC. I have one in my home.
    Look at the VX .
    Control is really slick
  • mattmia2
    mattmia2 Member Posts: 9,623
    HTP, Lockinvar, Viessman. Some of them have multiple DH calls on the boiler and can produce lower temps depending on the call which can be a convenient feature in some installations.
  • MarkC
    MarkC Member Posts: 18

    Ha! Plenty of people here would be happy with a modcon lasting 18 years, they'd claim that'd never happen. All depends on your perspective I suppose.

    I got about 17.5 yrs from an HTP 80M.
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,894
    Viessman Vitodens..very affordable these days..unparalleled qaulity & Warranties. Mad Dog 🐕