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Buderus 2107 Logamatic Control


I bought a house last fall with this unit and I cannot for the life of me understand how to get this thing set properly. I called Buderus directly and they would not help me set this up because I am not an "authorized" Buderus technician (just a lowly customer with no rights!). Anyways, I have a couple of issues I'd like to get cleared up before winter sets in. The first issue was I came home one day during last winter and the heat was completely off. I saw the indicator light and figured out how to reset it and the heat eventually came on, but it took hours for the house to warm up. I am concerned that if we go away for an extended period of time and this happens again, I'll come home to broken/frozen pipes. I'm sure it has something to do with the outside sensor and some sort of reference temperature. This did happen on a day when the temperature dropped dramatically. The second issue I have is that this is split into 2 zones; the upstairs (main living area) and the basement both have separate thermostats. I noticed over the summer, even with both thermostats turned all the way down, the basement baseboards were still warm. I have no idea on how to get this to turn completely off. I would greatly appreciate if anyone has any suggestions, tips or ideas! I've asked several HVAC guys I know and they won't touch them.


  • Bob Bona_4Bob Bona_4 Posts: 2,083Member
    Where are you located?
  • nickdavis44nickdavis44 Posts: 5Member
    Central New Hampshire
  • mikeylikesitmikeylikesit Posts: 3Member
    Nick, I don't see date on your post but assuming it's recent (9/4/15). I worked on Buderus G205 with R2107 control; I replaced heating circ. After, it was ON 100% and boiler stayed hot. I reviewed R2107 manual, contacted Buderus, confirmed this control keeps boiler hot all the time (hot start); further, it keeps heating circ ON all the time also, i.e. constant circulation -- this control does not have switching relays for heat circ, but does switch gas circuit on/off but maintains boiler hot within programmed limits.
    I asked Buderus tech how to make it switch heat circ & gas circuit when only when thermostats demand (in this case an end switch from zone control) : "remove it, replace it with relay/aquastat" was the answer. I was shocked frankly; boiler was in rambling ranch-style house with baseboard; there was no need for constant circulation. Original installer apparently didn't have a clue, didn't do their homework, but I too was ignorant of how this control works. I don't know if there's different versions of R2107 but I don't think so; there may be other Logomatics with switching features, but i'm not fond of these controls -- programming them is a bit bizarre at best.
    My solution was removing R2107, replacing with two Taco SR501 relays (one for heating, one for DHW indirect tank), controlling aquastat, manual reset aquastat, a Tekmar setpoint control for Buderus indirect …. i.e. a completely new control system.
    One must really really know what they're doing in this however !!
    Complicating matters in my case was G205 has gas power burner (120vac) -- thus I had to insure amp rating of aquastat & relay burner contacts exceed draw of burner load ….. not for the unknowledgable fer sure. That's my experience.
    One might find a single boiler control (e.g. Tekmar) that provides switching functions and outdoor reset, and there's other issues depending on burner type, whether you have zone valves etc.
    You need experienced professional. Hope that helps.
  • Bob Bona_4Bob Bona_4 Posts: 2,083Member
    It sounds like one issue from the Logo re reset curve and reference temp, one issue with the burner, and another issue with piping.

    Someone had to install that thing. Would find your local Buderus distributor, ask for an installer reference. Once the Logo is set up correctly, it shouldn't need babysitting. I have a bunch out there, probably more than I can remember bc I just don't get any issues past initial set up.

    You need eyes on this entire system
  • nickdavis44nickdavis44 Posts: 5Member
    Thanks guys, yeah I am reluctant to have Buderus get involved because from what I hear, they are very expensive with even their service calls..
  • Bob Bona_4Bob Bona_4 Posts: 2,083Member
    Give a local distro a call or ask the folks up at Londonderry for a referral. It comes down to a qualified contractor that can come and set you up. Won't be a Buderus rep. They will come for the contractor in cases.
  • RobGRobG Posts: 1,850Member
    Buderus is the manufacturer. You want to find a local company that has Buderus certified technicians. If you recently purchased the home I would recommend getting it cleaned and serviced for piece of mind. Nothing in this day and age is cheap. If the check engine light in your car lights up you take it to the mechanic. When it comes to HVAC, the mechanic has to come to you. That costs money. Otherwise be prepared for a cold winter and a more expensive emergency call. JMHO
  • R ManninoR Mannino Posts: 434Member
    The 2107 works great once it's programmed correctly. It sounds as though you have more than one issue going on other than just the 2107. The boiler will not be "hot" if you raise the WWSD, it will remain hot until the WWSD temp is achieved, then it will only fire for DHW.image
  • HillyHilly Posts: 409Member
    I called a Buderus rep before installing a 2107 once upon a time. We talked about 'stuff' and in the end he said give me a shout when you go to fire it all up. I did so and he talked me through the whole thing perfectly. I believe it's been going 4 or 5 years perfectly. This rep was up in East Coast Canada. Rep's that 'know' their products are a manufacturers best assets someways. If you remain stuck I'll see if I can find his number at the office on Monday.
  • heatheadheathead Posts: 89Member
    The 2107 is a great system. Check the placement of the outside sensor. Most likely you need to set it up properly, but I would ohm the outside sensor with corresponding tempature outside. The manual list the ohms and tempature in a chart. If the sensor is bad it can think it colder outside than it really is or vs versa.
  • nickdavis44nickdavis44 Posts: 5Member
    @Hilly..if you come across his number can you message me at [email protected]?

  • mxfrankmxfrank Posts: 21Member
    I have a 2107 on a G205, installed new 17 years ago. I've fired my last heating contractor ten years ago, and I've done the maintenance myself ever since. The reason is that I never found a tech who understood how the thing was supposed to work, and I think the only real expertise is somewhere in Germany.

    My feeling on Your reset is that you do have a sensor problem, but it's not the outdoor sensor. There is a well in the top of your boiler, where there are three logamatic sensors. One measures jacket temperature, and this is what displays on the screen when you query boiler temperature. There is a mechanical sensor which shuts down everything if jacket temperature is over 200F. You need to be very careful with this, because if you break the copper tube, then the entire control has to be replaced. And there is an electrical sensor which works with the knob on the front to set operating temperature: this is the likely culprit. (The knob should be set around 180, not to auto.) If this sensor is reading low, jacket temps will rise until the mechanical sensor signals the logamatic to cut off. You can measure the resistance of the sensor to verify, the spec should be in the manual. It may also be helpful to know that all Buderus temp sensors are electrically identical, including the water tank sensor and the outside air sensor, just in case you have difficulty finding parts.

    This control will certainly not require the jacket to be hot all the time. The boiler will only come on when one of the zones calls for heat, and DHW will have preference. You can really screw this up by fiddling with the switches on the front panel. Circulation in the heating zones should be controlled by the thermostats, regardless of what the boiler is doing. If you have hot water in your baseboards in summer, the thermostat/circulator wiring is suspect.

    One thing that may be helpful to know is that when sleeping in it's native soil, the Logamatic control is intended to control house temperature by varying the temperature of the circulating water. In such a system, water circulates continuously. This causes no end of confusion for owners and installers.

    My long experience with the 2107 in a rural area is that despite the best advice of the best technicians, you shouldn't change from the default settings. The reason is that the control works with volatile memory, and there's no way to add a UPS. When you have a power hit, all the careful adjustments you've made will disappear. It's safer to optimize the rest of the system around the defaults than to become dependent on a custom configuration. It's idiotic, but it's German, so it must be correct.
  • hfrogershfrogers Posts: 2Member
    I have a R2107. My new oil man will not touch it. I have been looking over it. Right know I have a BLR SENSR Err. I do not known were the sensor is located. Once I find it, it should be an easy job to replace it after I buy the part. I find that the boiler works well with the Riello burner. No carbon build up at all, which blows my mind since I have be cleaning a lot of carbon from my old hook up. Where can I buy the parts over the Web and where is the well located?
  • GWGW Posts: 3,488Member
    Golly gee when your car needs service to you call the manufacturer or do you bring your car to the local service man? The Buderus factory people aren’t hiding secrets, all of the manuals are available to everyone.

    It’s true most heating plumber guys won’t touch a 2107 with a 10 foot pole.

    You could pay the locals to remove the 2107 if it really haunts you

    Nick, what exact indicator light do you refer? Are you taking about the burner?

    And, you say your pipes are warm, do you have an indirect water heater?

    Yes, the thermostats may have nothing to do with the the boiler making heat.

    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • HVACNUTHVACNUT Posts: 2,753Member
    Showing a sensor error doesn't necessarily mean that the sensor is bad. It might just be doing what it's designed to do.
    The boiler sensor is the probe in the well at the rear of the boiler. You'll need to ohm it out to see what's what.

    You still need the boiler serviced every year by someone who has knowledge of the burner and boiler. A combustion analysis and smoke test must be done to make sure its operating safely and efficiently.
    He or she doesnt have to play with the 2107. Just switch to manual to run and press the chimney sweep button for the test.
  • nickdavis44nickdavis44 Posts: 5Member

    This post is 5 years old sorry. I got my burner straightened out, but I'll share what the main issue was. This is a direct vent system, which means the vent pipe is actually two pipes in one. The inner pipe is the outside air intake and the outer pipe is the exhaust. The intake pipe had rotted internally so it was pulling in the dirty exhaust which covered the sensor eye which would cause the burner to shut down on windy days. The pipe looked fine on the outside, but as a last resort we pulled it and found the issue, Once the new pipe was installed, the problem went away. However, getting the outside sensor offset correct can be a moving target.
  • GWGW Posts: 3,488Member
    LOL ok then let try and start new threads people

    I'm glad you're all good Nick
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • TAGTAG Posts: 193Member
    I have two houses with the earlier Eccomatic -- Basically the same thing as the 07. Buderus controls look more complex vs what they are .. but no one wants to touch them. Thankfully, when I was installing these in the mid 90's there was a guy named "Lew" at Buderus that was really helpful. About 10 years ago when I had a problem with one of the indirects and needed a new sensor. Buderus technical support had an answer -- replace my whole control with a 2107 .... they no longer sold the sensor and could not tell me if the sensor for the 07 was comparable (different part number).

    Found one on e-bay for $50.
  • hfrogershfrogers Posts: 2Member
    Does anybody use this anymore. [email protected]
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