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yellow stuff

drhvacdrhvac Member Posts: 189
coming out of flue pipe joints. Any ideas on what this could be? A new furnace and water was recently installed in this house. The house was renovated, and hasn't been lived in about 4 months. Heat has been set on 60 degrees because it has been vacant. Thanks.


  • kcoppkcopp Member Posts: 3,463
    sounds like....

    the flue gasses are condensing in the flue. Give us more info on the system....radiators? Baseboard? Hot water?Steam?hot air? gas? oil? Boiler model?
  • drhvacdrhvac Member Posts: 189
    that's exactly

    what I was thinking. 100,000 btu hot air furnace, 40,000 btu water heater. Like I said they are keeping the temp set low at the house because no one is living there. Also, I noticed that the bvent flue goes up the center of the house and terminates through the roof with no cap. There is some fake looking chimney around it made of metal. So i'm thinking cold air is pouring down that pipe and just condensing the gases. Make sense? Why is the condensate yellow? What's in the flue gases that makes water turn yellow? thanks again
  • pipekingpipeking Member Posts: 252
    edited February 2013

    is yellow. and u haven't said the fuel your using, if it was my guess it's NG.
  • pipekingpipeking Member Posts: 252

    is yellow
  • drhvacdrhvac Member Posts: 189

    it is natural gas. Is there a little sulfar in the fuel, or in the combustion air?
  • pipekingpipeking Member Posts: 252
    u r

    getting condensate in your flue or allot of rain. do u have a drip leg on the flue? got pics? and as for what kcopp ask for?
  • Pughie1Pughie1 Member Posts: 127
    Yellow Stuff?


      If my memory serves me correctly I believe the minium return air temperature

      furnace manufacturers like to see is 60* coming back to their units (Carrier

      & Lennox for sure) for any sustained time. This could cause condensation

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