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Buderus Logamatic HS2109 Malfunctioning

I have a Buderus Logamatic HS2109 that controls my Buderus G115 oil-fired hot water boiler and linked domestic hot water heater. This year ever sinceI turned the summer/winter switch over to summer operation the boiler water temperature has never dropped from 180. I also noticed the sound of the burner firing much more often than I think it should just for our hot water needs. I don't think this has happened in previous years. I'm sure this is wasting a lot of oil needlessly. Is there anything I, as the homeowner, can or should do to fix this, or is this only correctable by an HVAC contractor? My HVAC service technician won't be back until the fall for my regular service. Thanks.


  • Ironman
    Ironman Member Posts: 6,863
    Set the black temperature dail down to about 150*. This will also slow your domestic recovery rate.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    HVACNUT Member Posts: 4,562
    What temperature is the water heater set for? The dial next to the summer/winter switch.
    Max adjustment is 140 degrees, but there is a removable clip behind the dial to raise the temp to 176. Is is possible someone removed the clip?
    Is it possible your losing hot water somewhere (crawl space, hot tub) and the tank is not satisfied.
    Summer/winter switch might be faulty.
    I don't think they make the 2109 anymore. You could go with the 2107 with outdoor reset, or a conventional cold start aquastat. With a conventional aquastat, you would need to change the well, purchase a new aquastat for the indirect (the Buderus temp sensor won't be applicable) and rewire the DHW zone.
    The 2107 is fairly expensive, but with outdoor reset, and a host of other programming options, it's worth it, IMO.