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Need help with combo Navien boiler please

tscotto Member Posts: 1
I have a Navien combo unit that was installed 3 years ago and has been running fine with no issues. For the past few days the temp on the thermostat has been set to 75 but reading at 65. I changed the batteries in the thermostat for good measure. The baseboard is freezing cold. Boiler is running constantly with no error codes. The display shows the "radiator heat" sign and temps as usual. I'm a single mom with not very much knowledge of this kind of stuff so i apologize in advance.
Looking forward to hearing from you. Thank you.


  • Ironman
    Ironman Member Posts: 6,868
    Sounds like a circulation (flow) issue, not the boiler. We really need a lot more info.
    Can you post some pics of the boiler, its near piping, pumps and controls? Try and stay as far back when you take them so as to get as much as possible in each pic.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Gordy
    Gordy Member Posts: 9,514
    Agreed if it was working fine for 3 years. The first thing to check would be air in the system for the heating side. Possibly failed circulator.
  • SteveSEMA
    SteveSEMA Member Posts: 2
    Is it producing hot water on the domestic side? If so, It could be the 3 way valve which is not switching to the heat mode. I believe if it was the boiler circ it would be shutting down on high temp. Just my thoughts.
  • j a_2
    j a_2 Member Posts: 1,796
    Do you have a hot water faucet or shower valve leak...unless it’s unprogramed it will priority hot water..the software is different on the different models of combination units, if you feel comfortable go thru the parameters, there is as well on some models a factory reset button,that will reset it to how it came from factory..They really like to have the parameters set for individual situations
  • SteveSEMA
    SteveSEMA Member Posts: 2
    tscotto, If you are still having issues i would go on the Navien web site and look up a qualified tech in your area to service it.