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Direct vent Buderus boiler with Riello

Hvacbuderustech8
Hvacbuderustech8 Member Posts: 3
in Oil Heating

Hi everyone,

I have a direct vent Buderus G115/WS5 with a Riello F5. The vent is a FT4 Fields concentric termination. The exhaust pipe is a stainless flexible pipe. The system is 2 years old. The system will run good but over time it will have hard starts. The retention head gets full of soot and carbon causing the hard starts. I’ve adjusted the air with a combustion analyzer and performed a smoke test and it shows it’s burning clean. Can the wind blowing toward the termination cause a problem? Thanks for the help

Comments

  • SuperTech
    SuperTech Member Posts: 2,458

    Is that boiler and burner meant to be installed direct vent? The installation instructions for the G115/WS5 boiler with a Riello F5 show instructions for installation on a chimney, nothing mentioned about direct venting. Are you sure you have the F5 burner? The BF5 is designed for direct vent boilers.

  • LRCCBJ
    LRCCBJ Member Posts: 466

    If you think about the design of a concentric vent, you will understand that the intake is just behind the exhaust. This can work acceptably well when it is PERFECTLY calm. But, with the slightest bit of wind, the exhaust is going to circle back and enter the intake.

    In my personal opinion, a concentric vent is the worst invention ever thrust upon the typical unsuspecting public.

    The intake should be a minimum of TWO FEET away from the exhaust………..and preferably BELOW IT.

    When I do a mod-con, I try to run the exhaust up through the old chimney and use it as a chase. NO CHANCE of any exhaust entering the intake. The neighbors are pleased as well………………SILENT.

  • Hvacbuderustech8
    Hvacbuderustech8 Member Posts: 3

    The burner is a bf5, would you recommend to run a separate air intake away from concentric vent?

  • Hvacbuderustech8
    Hvacbuderustech8 Member Posts: 3

    Do you think the concentric vent is the problem or the burner needs to be adjusted? It has a 0.75 60a nozzle in it and I never adjusted the pump pressure. It runs good all summer long for hot water but when it gets a lot of run time during the winter the retention head soots up then it hard starts

  • Grallert
    Grallert Member Posts: 805

    You could try getting a reading from the intake at start up and while it's running. Your digital analyzer should be able to pick up any change.

    Miss Hall's School service mechanic, greenhouse manager, teacher, dog walker and designated driver

  • Big Ed_4
    Big Ed_4 Member Posts: 3,044

    I would first change the nozzle from an A to a W , much more forgiven with the fuel oil of today .. The A nozzle will break down the quickest .. If the termination is on the North West side of the house , it may be an issue …

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