Navien make whistling noise and sends propane in exhauset

Discussion in 'Tankless Water Heater Forum' started by mcbklyn, Mar 31, 2019.

  1. mcbklyn

    mcbklyn New Member

    Joined:
    Mar 17, 2018
    Location:
    New Paltz, NY
    Hi,
    I am homeowner trying to troubleshoot a problem with my heater.
    I have Navien NCB-240E installed 1 1/2 yrs ago (manufactured 2016) on propane.
    I have 500gl outside propane tank with 2 regulators (on the tank and on the house).
    A month ago after refill my Navien started to make short (1-3sec) whistling noise when it fires up on both domestic and heating loop.
    I also detect propane smell coming from exhaust pipe outside when it fires up.
    This wasn't happening before. It has been working fine since installation.

    First, I called propane company suspecting that there is something with their regulators/gas pressure. They came in twice and claim that all is good on their side.
    I called Navien trained plumber and he was with Navien cust.service on the phone for 3 hrs. He replaced pressure valve but this did not help. Navien told him the next step is to flash the system, which I don't want to do now.

    I suspect that this has something to do with how gas is burned inside the unit. Not sure if it might be related to new gas (it started happening after refill). I though that maybe fresh air intake got clogged. I took off heater's front cover and see that boiler does not make high pitch noise or it's only split second long. It still sends propane smell outside during firing. So it must be something related to gas/air mixture.

    Obviously plumber I hired and Navien support have no clue what the problem is so I wanted to ask community for help here before I make next move.

    Thank you.
     
    Last edited: Mar 31, 2019
  2. plumber69

    plumber69 In the Trades

    Joined:
    Jun 20, 2014
    Location:
    Prince Rupert, British Columbia
    Sounds like gas pressire is to high
     
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  4. Humberto

    Humberto New Member

    Joined:
    Apr 9, 2019
    Location:
    Clintondale NY
    I also have the same unit and I'm having the same issues after my gas company (Porco) filled up the tanks last month
     
  5. plumber69

    plumber69 In the Trades

    Joined:
    Jun 20, 2014
    Location:
    Prince Rupert, British Columbia
  6. plumber69

    plumber69 In the Trades

    Joined:
    Jun 20, 2014
    Location:
    Prince Rupert, British Columbia
  7. Humberto

    Humberto New Member

    Joined:
    Apr 9, 2019
    Location:
    Clintondale NY
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