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Navien Combi high efficiency units - feedback?

NJrealty Member Posts: 1
Hello, new to this site.
I flip homes and hold a few rental properties in NJ.

I was recently introduced to the Navien Combi. The installer said he's an expert, has it installed in his own house, and has been doing it for 8 years and rarely gets any service calls or maintenance issues.

However, online feedback and just about every other source I've looked into suggests these units are extremely problematic and not worth installing.

Does anyone here have experience working with or using these units?



  • bob eck
    bob eck Member Posts: 930
    There are many very good condensing combi boiler on the market today.
    First is the heating system connected to the boiler able to run and heat the building with low water temps?
    How many showers are in the house. Some combi boilers can deliver 4 plus GPM of domestic hot water. If I were you I would install 1.5 GPM shower heads to insure enough hot water for two showers. Plus it keeps your water and sewer bill down.
    Navien combi boiler their largest model is NCB-240E 199,000 BTU input combi boiler delivers 4.5 GPM (domestic hot water) at 77 degree temp rise but on the heating side it is limited to 120,000 BTU
    Take a look at the Lochinvar Noble largest combi boiler model NKC199N 199,000 BTU input with 4.6 GPM (domestic hot water) at 77 degree temp rise and on the heating side it will deliver up to 199,000 BTU input with no reduction on the heating side. Plus on the Lochinvar Noble if you need the larger size boiler for the domestic hot water output you can program the control to limit (reduce) the boilers firing rate for heating but is still will go up to 199,000 BTU for your domestic hot water needs.
    Get a heat loss done on your building don't over size the combi boiler for domestic hot water needs.
    Make sure the boiler is piped in the correct way and that the boiler is vented the correct way.
    You can buy a high efficiency 95% AFUE combi boiler but if not installed the correct way with outdoor reset control and if your heating system requires high water temps to heat the home you are waisting your money.
    What ever brand you go with does your heating contractor stock parts or does his go to wholesalers stock parts for the boiler they sell and install.
    Is your local gas utility or state offering any rebate for installing high efficiency gas combi boilers?