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Buderus G115 stinking up my basement

So I just moved into a home with the G115 and everytime it fires up I can smell burnt fuel oil. Turns out someone had put a Beckett burner on it that was never spec'd for the unit, so I luckily was given an home warranty when I purchased the home and was able to get the correct burner installed at no cost (was shocked). I still smelled the smoke after the install but gave it a couple days to burn off any oil or whatever from the installation and it is still sending a little exhaust in the room on every start.

A little about my exhaust tubing: It was piped into a brick chimney and had the smell, I took down the chimney and installed all new flue pipe in the basement with one 5 foot length of flue at about a 40-50 degree angle then straight up with all-fuel Duratech maybe 18 feet, still had the same smell, I taped everything, still smelly. I don't believe it's the exhaust tubing, nor did any of the oil techs that have been out.

Anyone have any ideas as to what is happening here? Thank you in advance.
Robert O'BrienHydroNiCK


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,257
    Isn't this a G115WS direct vent boiler and you're trying to fire it into the chimney?
    You need a competent professional to go over the whole system. Clean the boiler, check your chimney/flue pipe, and set the burner up with the right nozzle, draft, smoke, combustion air, etc.
    Also, is there enough combustion air when the burner runs?
    Is there a nice new high efficiency dryer sucking all the air out of the room?
    GBartSuperTechDan Foley
  • GBart
    GBart Member Posts: 746
    edited April 2018
    Agreed, you need a Buderus trained technician.

    Do you have a CO detector or alarm?

    I saw a Buderus put out 30,000ppm CO because the baffles were installed wrong.
  • SuperTech
    SuperTech Member Posts: 1,942
    edited April 2018
    That boiler and burner need to be set up to the manufacturers specifications, with proper combustion analysis performed. And it sounds like it will need a lot of cleaning!

    Please don't tape the flue pipe.
  • GBart
    GBart Member Posts: 746
    from manual-- Sealing of the Vent Piping:
    The discharge side of the sealed combustion venting system operates under a slight positive pressure. It is
    of vital importance to seal all flue joints and screw penetrations to prevent leakage of flue gases into the
    building. Pipe joints and other possible flue gas leakpaths should be sealed with high temperature silicone
    (500 ºF rated silicone, G.E. 106 or equivalent), or high temperature tape (360 ºF rated aluminum foil tape,
    VentureTape 3520CW or equivalent) as necessary.
    The venting system shall not be pierced under any circumstance after initial installation.
    Combustion measurements shall be performed at the exhaust termination and/or overfire. The breeching
    can be pierced for testing as long as the hole is sealed airtight with a bolt, washers and high temperature

    starts on page 3

    amazing things, these manuals

    https://www.bosch-climate.us/files/201208201508230.115SCIM_G115_Installation Manual_en_12-2006.pdf
  • GBart
    GBart Member Posts: 746
    edited April 2018
    you stated--- " I don't believe it's the exhaust tubing, nor did any of the oil techs that have been out."

    how many tech's exactly?, did any refer to the manufacturers manual??

    did any check for CO ??
    HVACNUT Member Posts: 5,258
    Is there adequate combustion air? Is it the Beckett NX?
    Shouldn't be too hard to figure out.

    Amazing things, these analyzers.
  • SuperTech
    SuperTech Member Posts: 1,942
    @GBart I stand corrected. I dont work on a lot of Buderus and I have a dislike for foil tape on the flue pipe.

    Thanks for setting me straight on that.
  • GBart
    GBart Member Posts: 746
    It doesn't hold up, several manufacturers are now saying to seal it with hi temp silicone, Buderus states that or hi temp tape but I haven't seen a tape hold up for years, silicone holds up.
  • GBart
    GBart Member Posts: 746
    HVACNUT said:

    Is there adequate combustion air? Is it the Beckett NX?

    Shouldn't be too hard to figure out.

    Amazing things, these analyzers.

    you have to use the manuals
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,512
    Both Beckett NX and AFG are approved with G115 so that isn't your problem. Need someone with a combustion analyzer and who knows how to use it
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • lchmb
    lchmb Member Posts: 2,997
    Gbart the manual you listed is for a direct vent boiler. Being this is chimney vented it will be negative at breach and for that reason taping/sealing should not be necessary.. It sounds like a setup issue. Does it do it every time it runs? Does it do it when it shuts down? Does it rumble when it starts? Have they done the filter at the tank?
  • rick in Alaska
    rick in Alaska Member Posts: 1,429
    Check the door gasket.