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Buderus G115 ?


Inspected a house yesterday with a Buderus G115 w/Riello burner. (G115/5) When I opened the burn chamber door a minute into the burn cycle there was a considerable flow of exhaust gases coming out into the living space. It continued the entire time I had it open. For any other boiler (common boiler I should say) this is an immediate flag for improper draft. The homeowner was on the phone with the company that installed it within minutes and they were telling him this was totally normal for this boiler as it is a positive pressure boiler. Unfortunately Buderus is not a common install around here and I'm lucky if I see one every couple years. Can anyone shed some light on this for me.

A couple other notes about the install & performance... I noticed an exhaust/oil odor as soon as I opened the basement door at the top of the stairs. The homeowner told me he has been having problems ever since it was installed with stains running down the outside of his stucco chimney. The flame character and color was pretty poor and the burn chamber had quite a bit of debris in it for a boiler that was supposedly just serviced in Feb. of this year. This along with the deteriorated relief valve doesn't give me any confidence in this installer.

And lastly, The service ticket from a couple years ago stated 87.5% combustion efficiency but the one from this past feb. was 84.6%...

Any opinions would be greatly appreciated. Any that can reference some form of documentation would be even better. I already scanned the install manual and didn't see anything relative.

There was an error rendering this rich post.


  • Steamhead
    Steamhead Member Posts: 16,904
    edited August 2010
    I believe that is a pressure-fired boiler

    like most 3-pass units these days. It's first-class equipment.

    The other things need immediate professional attention. The flue gas temp may be low enough that the chimney is condensing. Has the chimney been lined?

    Try the Find a Professional page of this site if you need a pro. Where are you located?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • JerseyWreckDiver
    JerseyWreckDiver Member Posts: 14
    Don't think so

    The homeowner says they told him they would put a liner in after he complained about the staining the first time. Since then, nothing has changed. Unfortunately it has a clay tile roof, which I wasn't about to walk on, and a Spanish mission style chimney with a flue termination that I just couldn't see otherwise. The flue connector is high temp RTV'd into a terra cotta nipple so I don't know if it is or isn't.

    The house is in South East Sussex County NJ, Adover. He's got one of the bigger HVAC companies that installed it and have been doing all his maint. for years. I'm less fond of them now then I ever was.

    There was an error rendering this rich post.

  • clammy
    clammy Member Posts: 3,113
    minor notes

    The g115 also has baffles which can be removed to raise the stack temp if need be to help pervent flue gas condensate in the chimmey it will raise the stack temp and also lower the eff  a little bit ,also there are i believe  there are2 by pass notches that can be chiseled  or ground out if there is to much over pressure in the combustion chamber you can contact buderus tech service if need be ,i have installed about a dozen or so g115 and a few g215 great boilers in the smaller g115 they can at some time be a little tough to set up and get perfect .It should be no be issue for some familar with oil who has worked on both reillos and buderus peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • meplumber
    meplumber Member Posts: 678
    Positive Pressure Burner

    Every had the burner ignite with the drawer assembly door off while trying to bleed the oil line? 

     I had a helper do it once and his eyebrows still haven't grown back.

    The Riello is a high static burner.  In the G115 it is pushing a high positive pressure to overcome the European Style 3 Pass design.  I am almost suprised that you didn't get flames coming out of the door. 

    As to your staining question, in Maine, the chimney must be lined on all new boiler installations.  That unit is probably running at a 325 deg F stack temp or somewhere in that neighborhood.  If you have a tall masonry chimney with very much of it exposed outdoors, then you will have flue gas condensation.  Line the chimney with an approved metal liner.
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