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  1. #1
    Join Date
    May 2008
    Location
    Kansas City Area
    Posts
    13

    Gas Vent Pipe Dripping White Substance

    Hi All-

    I have a Bryant Plus 80 furnace with a heat pump-A/C combo; typical 2-story house design with basement - age: 4-5 years.

    From a previous discussion here (based on the SEER rating), the A/C compressor isn't large enough to meet the cooling demand. So, if we use the stove, I have to open the damper to the kitchen to cool that area, and close it up to give the main-floor and upper-floor areas. The temp creeps higher from the setpoint until the sun goes down. Technicians have been out for various problems, and apparently it's "just how it is".

    Tonight I noticed a damp, white crystalline substance that had dripped on top of the furnace door. It's coming from the main furnace vent at the first pipe connection. It doesn't have a smell and looks to heavy in mineral content. It forms like an icicle or cave drippings.

    We just returned from a 9-day vacation where the hot water tank was set to "vacation". The furnace gas vent enters a Y connection by the hot water tank and up to the roof.

    I fired-up the burner to see if there were any blockages. I smelled some natural gas, but probably normal.

    So, what could this stuff be? Any concerns?

    Thanks in advance...

    RH77

  2. #2
    Join Date
    Mar 2003
    Location
    PA/DE area
    Posts
    1,535
    Is it a masonary chimney?
    It's NOT the BRAND,it's the company that installs it!!!!!

  3. #3
    Join Date
    Apr 2009
    Location
    Pan Handle, Fl
    Posts
    600
    It's probably sulfur. What type of flue or chimney do u have. Google chimney and sulfur.

  4. #4
    Join Date
    May 2008
    Location
    Kansas City Area
    Posts
    13
    It's not a masonry chimney...

    It has a power/fanned flue and metallic all the way up to the cap.

    The smell doesn't have a hint of sulfur or even an orange tint.

    Is there a high-temp sealant used anywhere? We have a CO detectors, but this strange stuff has me worried.

    I can take a pic if it would help...

    Thanks again....

    RH77

  5. #5
    Join Date
    Jun 2009
    Location
    Kamloops B.C.
    Posts
    31
    Pics are always good I just looked at a home with a similar situation and I found that the roof jack was worn and water leaked in when it rained very little but it leaked inside the home and just a small sign white crystal looking from the inside of the pipe showed at the first connection. We repaired the roof jack and never heard anything since.

  6. #6
    Join Date
    Jul 2009
    Location
    Arizona
    Posts
    81
    how much is comming out of the vent? Did you wipe it off or is it still there?

  7. #7
    Join Date
    May 2008
    Location
    Kansas City Area
    Posts
    13

    Pix

    We've gotten a LOT of rain this year. Anyways, here are some pix...

    The first is the main flue off of the burner, note the stream of white, powdery stuff:



    Some of the spatter that turned me to the investigation (the wet beads are spray from a small air leak close to the condenser):



    The Y-split:



    ...and finally the main flue exit:



    RH77

  8. #8
    Join Date
    Jun 2009
    Location
    Anoka, Minnesota
    Posts
    26
    You are all missing the obvious here. This looks like a classic case of oversizing the vent pipes. What is the model of the Bryant furnace? If it is a 312A or 315A it is a 2 stage unit. 310A and 311A are single stage.
    First of all if this is a two stage furnace, it must be vented with class B double wall all the way from the outlet of the furnace which is 4" to the main class B chimney vent. The reason for proper vent sizing per the GAMA vent tables (provided in the manual) is to keep the flue gas temperatures above their dew point to prevent condensation inside the vent connector and chimney. By the looks of the pictures, the vent connector is single wall and looks like 5 or 6 inch. The connector needs to be 4" to the Y connector. In our state, this venting arrangement is not legal. The main chimney needs to be sized from the GAMA vent tables. The diameter is detemined by the total height, connector rise and total input in BTU's.
    This white stuff is most likely from the flue gases cooling and condensing which runs down the pipes and forms oxidation from the aluminum and galvanized metal. Kind of like rust. Chimney won't last long this way and it runs into the furnace combustion blower collector box area. That won't be covered under warranty. Could get spendy down the road.

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