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DV Buderus question

Today I had a discussion with a contractor in regards to a DV Buderus boiler, and we are on opposite sides of this thread. He was at a job where the installer had installed the intake air on a different wall than the hood. This being the first time he had seen this he questioned whether this was okay. He said no, because the flue temps would be too high causing possible clearance to combustable issues. He feels that the incoming air cools the flue gases to an acceptable temperature to cover clearance issues.....
I feel that there was a reason that it was installed this way, possibly because of cross contamination. I feel this is an acceptable installation method as the baffles within the boiler will help reduce flue temps. I feel as though the only effect will be on the burner efficiency.
Please help..This is more for my understanding than anything else. If I am correct is this also acceptable on a DV Biasi boiler which does not have baffles ?



  • tim smith
    tim smith Member Posts: 2,738
    termination of dv appliances.

    If the specs are set up for the dv terminal to go into the double wall sleeve then yes it must be done that way. No ifs and or butts. Tim
  • ScottMP
    ScottMP Member Posts: 5,884
    I beleive

    it has to do with balancing the flue and combustion chamber. The exhuast and intake must come from the same location so as to not have problems with preasure changes. Also the combined flue is to warm the intake air for better combustion not to cool the flue.

    Check manufactures instructions, all will state that the flue and intake must come form the same location.


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  • Joe@buderus
    Joe@buderus Member Posts: 165
    Direct vent

    The fresh air intake and exhaust must be on the same wall to equalize the pressure. The concentric termination (FT4) uses the fresh air intake to reduce the clearances. The AT4 (exhaust and fresh air intake are seperate) uses an insulated exhaust pipe to reduce clearances.
    Both terminations must be installed correctly to insure proper operation. Please contact us if there are any questions. 1-800-283-3787.
  • Constantin
    Constantin Member Posts: 3,796
    Having devleoped a DV water heater,

    ... I can only say: Install both vents concentricially, on one wall, period.

    Anything else begs for ΔP differences between the vent terminals, leading to bad combustion. The fan blowers can only respond so quickly to gusts, so the ideal installation features no ΔP as the wind howls outside.

    It can be done, but it takes a lot of work. Most vent terminals I see don't pass muster with my experience.
  • S Davis
    S Davis Member Posts: 491

    Hey joe I called Buderus Tec Suport and asked about venting a GA124/17 and was told i could run the vent out the roof and combustion air out the side wall with no problem were they wrong?

    S Davis

    Apex Radiant Heating
This discussion has been closed.