Page 1 of 3 123 LastLast
Results 1 to 13 of 32
  1. #1
    Join Date
    Jun 2007
    Location
    Bucks Co PA
    Posts
    364

    Negative chimney draft -oil furnace

    I recently had a complete new system installed; Carrier heat pump and variable speed oil furnace 58VMR. I notice oil furnace exhaust fumes in the basement when the oil furnace runs.

    Because it is a duel fuel system, the oil furnace does not run that much until the outside temp gets to about 30* or below.

    I called the company that "hooked-up" the oil furnace (the install company does not do oil) and the fellow found a negative one draft from the chimney. He is puzzled by this situation. When the oil furnace runs for a few minutes the draft is positive as it should be.

    The oil guy said to "just run the oil furnace only".

    It seems to me that it would be "natural" to have a negative draft in a "cold" chimney. Am I correct ??

    If that IS the case how do I prevent "exhaust fumes" in the basement ?? Any suggestions ??


    BTW, I just had a contractor (other than the ones associated with the install) seal the duct work as best he could.
    .

  2. #2
    Join Date
    Sep 2002
    Location
    Northeast Ohio
    Posts
    4,842
    + = pressure = no draft = oil fumes
    A good HVAC tech knows how, an educated HVAC tech knows why!

    DEM


  3. #3
    Join Date
    Aug 2008
    Posts
    42
    Ask him what -.04 is and what it means to him.

  4. #4
    Join Date
    Oct 2002
    Location
    Yo.... Here!, I'm right here..
    Posts
    6,236
    It seems to me that it would be "natural" to have a negative draft in a "cold" chimney. Am I correct ??
    No
    cold chimneys don't draft naturally warm ones do..........I don't think you should be seeing a "positive draft" at all anywhere....anytime with a resi system such as this.......

    Hey get an Oil guy in there to set it up, just pay them or buy their service contract and their oil, it'll only make things safer for you and your famly.......... or did you get the cheapest price and are willing to gamble your family's life.............

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,935
    Your oil guy that was there. Is not thinking clearly, to say the least.
    The flue and chimney should both be in negative draft when the furnace is running, or you WILL get fumes.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Jan 2006
    Location
    Powell River, BC, Canada
    Posts
    763
    Some oil furnaces like the Carrier have a + OVER FIRE draft usually around +.01". All oil furnaces should have a - FLUE draft of -.02 to -.04".
    Where are you? Are you done yet? I got ONE more call for you.....

  7. #7
    Join Date
    Jul 2005
    Posts
    717
    Jack2007; do you have a "barometric" damper installed onto the vent pipe to the chimney? if so, is it set up right?
    If not, get one and have it set up by a pro to neutralize any positive/negative pressures.
    Settings are normally .03 to .02 w.c. using a draft gauge, also have the pro check stack temp.... usually 450 * (+ - 40*)

  8. #8
    Join Date
    Feb 2008
    Location
    Altmar, New York, United States
    Posts
    4,619
    Quote Originally Posted by gasguy View Post
    Some oil furnaces like the Carrier have a + OVER FIRE draft usually around +.01". All oil furnaces should have a - FLUE draft of -.02 to -.04".
    YES, BUT YOU STLL NEED A NEG DRAFT AT BREECH.

  9. #9
    Join Date
    Jun 2007
    Location
    Bucks Co PA
    Posts
    364
    Thanks to all for replies.

    Rlattime3 Ask him what -.04 is and what it means to him.
    This on the receipt;
    "smoke pipe and overfire has down draft +.02 breech, +.02 overfire....fumes coming out draft regulator.........ran burner draft was -.04 breech, -.02 overfire.............draft good immediately after burner shuts off"
    Roscoe
    No
    cold chimneys don't draft naturally warm ones do..........I don't think you should be seeing a "positive draft" at all anywhere....anytime with a resi system such as this.......

    Hey get an Oil guy in there to set it up, just pay them or buy their service contract and their oil, it'll only make things safer for you and your famly.......... or did you get the cheapest price and are willing to gamble your family's life.............
    I had a highly recommended HVAC company (recommended by a pro on this site) do the install.

    beenthere
    Your oil guy that was there. Is not thinking clearly, to say the least.
    The flue and chimney should both be in negative draft when the furnace is running, or you WILL get fumes.
    OK. When he said "negative draft" he meant cold air coming down the chimney when the furnace was NOT running.
    deejoe
    Jack2007; do you have a "barometric" damper installed onto the vent pipe to the chimney? if so, is it set up right?
    If not, get one and have it set up by a pro to neutralize any positive/negative pressures.
    Settings are normally .03 to .02 w.c. using a draft gauge, also have the pro check stack temp.... usually 450 * (+ - 40*)
    Yes there is a "barometric" damper. The guy who came said every thing except the draft (cold air coming DOWN the chimney) was normal.

  10. #10
    Join Date
    Oct 2002
    Location
    Yo.... Here!, I'm right here..
    Posts
    6,236
    quote: jack2007
    This on the receipt;
    "smoke pipe and overfire has down draft +.02 breech, +.02 overfire....fumes coming out draft regulator.........ran burner draft was -.04 breech, -.02 overfire.............draft good immediately after burner shuts off"
    This sounds normal.... -.02 O.F. and -.04@breech

    .......are you saying that it lights off hard initially, then runs fine and then the draft #'s are good. Or better put HOW does it light off.........

  11. #11
    Join Date
    Jun 2007
    Location
    Bucks Co PA
    Posts
    364
    Quote Originally Posted by Roscoe View Post
    quote: jack2007


    This sounds normal.... -.02 O.F. and -.04@breech

    .......are you saying that it lights off hard initially, then runs fine and then the draft #'s are good. Or better put HOW does it light off.........
    All I know is there are fumes in the basement.

    The oil guy is the one who believes cold air should NOT be coming down the chimney when the furnace has been off for a while.

    The contractor who sealed the ducts (but does not do oil), made a comment that maybe I should look into having the barometric damper AND furnace air intake vented to the outside.
    .

  12. #12
    Join Date
    Oct 2002
    Location
    Yo.... Here!, I'm right here..
    Posts
    6,236

    No barometric....??

    Ya definitely need a barometric......as stated above by deejo

  13. #13
    Join Date
    Jun 2007
    Location
    Bucks Co PA
    Posts
    364
    Quote Originally Posted by Roscoe View Post
    Ya definitely need a barometric......as stated above by deejo
    There IS a barometric damper.
    .

Page 1 of 3 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event