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Buderus with 2107 + Wood stove = ???

Swamp_Yankee Member Posts: 15
We have a 2600SF old farmhouse-about half is late 1800s construction the other half (3/4 of the second floor) is a 1990s addition. The whole thing is heated by a Buderus Logano G215 with 2107 controller with two zones, one downstairs one upstairs. The zones are controlled by Nest E (the cheap ones) thermostats setup as simple "dumb" thermostats (no temperature learning, etc...)-they are essentially regular programmable thermostats that can be monitored and/or manipulated remotely. The zones feed slant fin baseboard throughout the house. On the first floor we have a beautiful old stone open fireplace that, nice and cozy as it is, is a huge waste of heat when its operating. Oil usage with the Buderus is very low for a house of this size (we keep it at 70°F during the day and drop back to 63°F at night) so I'm not looking to install a wood insert to save a ton of money on oil, but rather to not waste heat (and oil) while enjoying a nice fire and adding some extra warmth to the house in the process. The question is, is this going to "confuse" the 2107 and end up wasting fuel?

I envision the following scenario: Let's say its a cold night: 25°F, which the 2107 knows by virtue of the outdoor temperature sensor. Upstairs I get a nice fire going in the insert, and before long the entire 1st floor of the house is a toasty 72°F, which means that the Nest E then tells the downstairs zone valve to close because the setpoint on the thermostat is 70°F. The living room is not far from the staircase so theoretically warm air should easily rise to the second floor as well, perhaps raising the temperature beyond the upstairs Nest's setpoint as well. At that point the 2107 is downstairs seeing that the outdoor temperature is in the mid-20s and dropping but the boiler water is essentially just recirculating because both zone valves are closed and the only call for heat is from the DHW tank. Is the 2107 simply going to dial back the water temperature accordingly?


  • Ironman
    Ironman Member Posts: 7,375
    The 2107 is not an "on demand" control. In other words, it doesn't come on because the thermostat calls. It maintains a target water temp based on outdoor temperature. The thermostat energizes a pump relay and as the water temp drops in the boiler, the 2107 fires the burner to achieve its target temp. So if the thermostat is satisfied (for whatever reason), the water temp in the boiler will remain pretty much the same.

    So, the fireplace won't confuse the 2107.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • BDR529
    BDR529 Member Posts: 285
    Splittin' hairs, Buderus running good. Let it go don't overthink it.
  • Big Ed_4
    Big Ed_4 Member Posts: 2,783
    You can install the optional room sensor to help with your concerns .
    I have enough experience to know , that I dont know it all