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Laars MFTCW 199 Harmonic Noise

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JLabouef
JLabouef Member Posts: 1
in Gas Heating

When my boiler is in high fire there is a brief harmonic humming noise in the boiler near the gas valve. Anyone experience this? 2" vent and intake. Propane fired. Laars tech help said to close the gas cock until the noise goes away then leave it there. Worked for about a year but now it won't fire unless the gas cock is wide open.

Comments

  • GroundUp
    GroundUp Member Posts: 2,368

    Combustion is most likely out of tune and needs to be adjusted using a combustion analyzer. It could also be several other things like CSST piping, low gas pressure, undersized regulator, plugged intake, etc but this is a pretty common symptom of a boiler that was not properly commissioned. Being a Mascot that's cheap online, would it be safe to assume that this was not professionally installed and commissioned?

    Ironman
  • Ironman
    Ironman Member Posts: 7,730

    I can’t believe that tech support would advise you to do something as dumb as that.

    As mentioned, it’s required that the boiler be set up with a combustion analyzer and set to factory specs.

    By running it with the gas cock partially closed, you’ve probably created a situation that’s worn the burner and/or the electrodes out.

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    GroundUp
  • hot_rod
    hot_rod Member Posts: 25,357

    when was it last opened up and cleaned on the combustion combustion slide?

    Also scaling on the water side can cause noise. I would clean inside and out, then have it readjusted with an analyzer.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream

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