Page 1 of 3 123 LastLast
Results 1 to 13 of 37
  1. #1
    Join Date
    Jan 2008
    Posts
    13

    lack of velocity

    Have a carrier 90% forced air nat gas system that was installed in 1992 by previous home owner. We've been here three years and this year no velocity coming from ducts. Can't get house ove 69 degrees here in Michigan. Replaced 4 inch filter, servcieman replaced inducer motor (it locked up), and checked system said all is ok. Blower works, flame burns. just not getting air out of the ducts. Dampers are open. Hot air duct above furnace is cool to touch. Any thoughts? Thanks

  2. #2
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    By your symptoms no air flow this year, furnace running can't get above 69 in house, I would think your furnace should be cycling on high limit. Secondary heat exchanger or evaporator dirty, or blower or all three. The furnace cabinet should be hot.

  3. #3
    Join Date
    Sep 2006
    Posts
    1,253
    Do you have an A/C coil above the furnace? If so it may be clogged and restricting air flow.

  4. #4
    Join Date
    Jan 2008
    Posts
    13

    no velocity

    thanks, your replies make sense, do have CA. Wouldn't 4 inch air filter trapped debris?

  5. #5
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    Quote Originally Posted by milender View Post
    thanks, your replies make sense, do have CA. Wouldn't 4 inch air filter trapped debris?
    You could have air leakage around the filter and 15+ years.

  6. #6
    Join Date
    Jan 2008
    Posts
    13
    Is the cleaning normally done by the HVAC guy or one of the "duct Cleaning" companies?

  7. #7
    Join Date
    Jul 2001
    Posts
    3,112
    Was the blower motor changed in the past? The rotation could be wrong.

  8. #8
    Join Date
    Jan 2008
    Posts
    13
    Inducer motor was replaced two weeks ago but not blower motor. Could blower connection be reversed in disassembly and reassembly? Work was done by licensed HVAC company.

  9. #9
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,939
    Quote Originally Posted by milender View Post
    Hot air duct above furnace is cool to touch. Any thoughts? Thanks

    Are you sure the a/c and heat are not both running at the same time?
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  10. #10
    Join Date
    Jan 2008
    Posts
    13
    outdoor air unit is not running. If it was would it restrict air flow to ducts? I'm getting heat at the ducts, but no velocity. Thanks

  11. #11
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,939
    Quote Originally Posted by milender View Post
    outdoor air unit is not running. If it was would it restrict air flow to ducts? Thanks

    Yes if the coil was froze up or freezing up.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  12. #12
    Join Date
    Jan 2008
    Posts
    13
    Inspected A coil, no freeze up, no build up, vac'd it out anyway. No improvement. Thanks. Some one mentioned blower running backwards, mine rotates clockwise looking from the filter.

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,903
    Not knowing what furnace you have, or which side the air filter is on, can't tell if thats teh correct rotation or not.

    When you looked to see if the coil is clean. Did you look on the side toward the blower,or the side toward the ducts.
    Contractor locator map

    How-to-apply-for-Professional

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

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