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Buderus rumbling.

scrook_2
scrook_2 Member Posts: 610
in THE MAIN WALL
Or an
an 80°W vs. the 80°B? Buderus cites both types, depending where you look.

Comments

  • ejk_2
    ejk_2 Member Posts: 9
    buderus rumbling

    I have a G-115-21 with a riello burner. Everything is set to specs. nozzle is a .50 80deg. B. I just lined my chimney with a 5" insulated liner.Pump pressure is 145#'s running 0 smoke
    350 deg stack temp,-.02 breech draft +.01 over fire draft.Any ideas?
  • JOE_104
    JOE_104 Member Posts: 15


    check buderus web site see if burner set up to new spec/provision also try 70 w nozzel or/& try liner on chamber floor area to muffler down combustion noise
  • dana_3
    dana_3 Member Posts: 57
    buderus rumble

    the W nozzles work best. do you have 24"of horizonal flue pipe right off the back of the boiler, before any 90's. if everything else is ok, you should be in the 13% co2 range
  • A.J.
    A.J. Member Posts: 257
    Rumble

    If your tanks are in an unheated area you might want to try turning up your pump ressure to 190# to get better amotization.
  • ejk_2
    ejk_2 Member Posts: 9
    first year

    this is the 3rd season and this is the first time it happened. it doesn't rumble all the time either.
  • psd_3
    psd_3 Member Posts: 86
    Buderus rumbling

    Can you describe the rumbling ...

    when does it happen ... only at startup/ignition, or continouous?

    where is it heard ... just at particular locations around the boiler, or everywhere?

    are your draft readings stable, or bouncing around?

    what does the exhaust noise directly at the breach of the unit sound like ... smooth, or pulsating?

    what are your CO2, O2 and CO readings and are they stable?

    If it is rumbling due to a combustion instability or an ignition issue, then it is important to correct it for safe reliable operation.

    It is not uncommon to hear a reverberation/echo from the exhaust noise of these units that sounds like a rumble at various locations away from the unit. Some configurations sound like a clothes dryer tumbling a load of clothes that can be heard ~10ft away from the breach. On the otherhand, they sound perfectly smooth at the breach or right it front of the unit or from the rest of the house. An exhaust muffler from Buderus may help this sort of condition.



  • psd_3
    psd_3 Member Posts: 86
    But ...

    you said that you just lined your chimney with a 5" liner ... which can change the characteristics of the draft and sounds of the exhaust. These can vary with outside temperture and humidity.

    As stated before ... you will want to analyze your combustion parameters for stability when the condition is actually occuring.
  • ejk_2
    ejk_2 Member Posts: 9
    happening before

    I thought it was rumbling because of the masonary chimney.It was an 8x8 tile lined exterior chimney. Woke me up at 4 am rumbling. That was my reason for lining the chimney. Didn't help.
  • Leo
    Leo Member Posts: 770
    Not saying you don't have an issue

    I'm not saying you don't have an issue but Riello burners generally have good comments, the one negative one is chimney roar.

    Leo
  • psd_3
    psd_3 Member Posts: 86
    Rumbling

    Can you provide a response to my previous questions near the top of this thread ... just below your initial post?

    I too hear rumbling with a Buderus/Riello combination ...
    but in my case I know it's due to chimney/exhaust noise. I have a clean flame with no pulsations and the rumbling is heard only in specific locations around the boiler. I have also found that removing the barometric damper can improve the exhaust noise if you can tolerate the potential draft variations.
  • ejk_2
    ejk_2 Member Posts: 9
    response

    co2 is 12.3. The burner will light smooth then 10 seconds later start shaking then it drops out and relights. same thing smooth then rumble then drop out. after about ten retry's it then stays on and the rumble fades.
  • psd_3
    psd_3 Member Posts: 86
    Ahh ....

    Ok ... this is very important info and has more to do with startup conditions than steady-state operation.

    Are you using inside or outside air for combustion? In other words are you using a Riello BF3 or an F3?

    Who did the last adjustment and what did they change? Did someone perhaps gap the electrodes a bit tigher (narrower) than before?

    Here are the things to consider in order of importance -

    Electrode spacing and positioning ... Riello calls for 5/32's (4mm) but others (including Buderus) suggest that wider is better. I recall Buderus recommending a sloppy 6/32's and I recall tech's working with Riello recommending as much as 1/4".

    Increased pump pressure may improve the condition by improving atomization of the fuel droplets. I have seen 165 psi recommended in Buderus posts.

    Cold combustion air worsens the condition. If you are using outside air for combustion, then you may want to try mixing it with some inside air to temper it.

    CAD cell not likely an issue given it will run fine after a number of attempts.

    A 12.3% CO2 reading is pretty nominal as long as coupled with #0 smoke.

    Given that this is a recent change, I would bet on an electrode spacing/position issue. If the last one to work on the setup increased the air band setting then this could be a contributor, but 12.3% CO2 is a very reasonable setting for this combo and should work fine. I think you would find less sensitivity with a higher pump pressure and warmer combustion air too.

    As a last resort it could also be a bad nozzle ... defective or partially plugged resulting in a poor spray pattern. These small nozzle sizes are not very forgiving.

    By the way ... could it be that the first 10 seconds that you hear is the pre purge interval (standard for Riello controls) and the burner then tries to light and does so with poor ignition and drops out immediately?
  • psd_3
    psd_3 Member Posts: 86
    Buderus rumbling ... any update?

    ejk - any update on your situation?

    Thanks,
    Sid
  • Chris. Rorke
    Chris. Rorke Member Posts: 4
    Riello f3/ bude 21

    Question, electic intake damper or hydraulic? If hydraulic , does it open quickly when burner starts? Is the burner a Bude accesory or off the shelf Riello .. what length burner tube & how far is it inserted? Into boiler door &/or combustion chamber. Concentricty of fire pattern can be impotant. Just having the inspection port open can throw it off! I've had good luck with the Danfoss 80 Degree X .50 AH nozzle @ the factory pressure of 10 bar (i.e. 145psi) Regards Chris.
  • Carter
    Carter Member Posts: 3


    Is there an update to this issue. I have the same problem on a new install but when the installer comes over the burner purrs like a kitten. I'm going to try and capture it on video for him but it's hard to caught because by the time I get down to the basement it's running fine and it doesn't happen all the time.
  • R Mannino
    R Mannino Member Posts: 441
    Start up rumble

    I have a G115/21 with a F3 Riello and have had a similar occurrence during start up. However it only happens to me when the outside temperature is below about 20-25 degrees. I have a UST, the lines are exposed for several feet outside and the chimney is a relatively short prefab. I do not think it is a draft situation, I believe it is a cold oil/impingement issue, she smokes like crazy when it happens. Anything above these temps she's fine. I think I need to hone my setup skills. Ron
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