Results 1 to 2 of 2
  1. #1
    Join Date
    Jul 2012

    Default No trunk lines off of furnace?


    Is this bad? We have all our offshoot vent pipes coming straight off the furnace instead of trunk lines. I've tried to attach a photo, but had trouble until I zipped it up and then attached it.

    Our house doesn't get much heat (or cool air in summer), except for the basement. I've confirmed there are not blockages in the vents, but there are numerous leaks. Will fix those first. We also have return vents that seem to be clean and in good condition. The furnace was replace 2 years ago, but the problem of low air flow has been there for nearly 20 years.

    But I'm curious to hear if this 'design' is bad. I wonder if the air would flow more freely if offshoot pipes ran of a trunk instead of the furnace itself.

    Attached Files Attached Files

  2. #2
    Join Date
    May 2011

    Default Re: No trunk lines off of furnace?

    They usually call those "octopuses". IN some cases, these were originally gravity furnaces, that used convection with no blower. Sometimes the ducts were asbestos insulated.

    If it's a older furnace, it may have fairly low airflow if <80% efficient) and just isn't moving a lot of air. IT might also be oversized and has too much restriction so much of the heat goes to air leaks.

    Hard to tell form here.

    IF there are no trunks, then the supplies might be locted in the center of the house and just aren't distributing the air well, and it instead short circuits to nearby returns.

    Finally if you have too many registers, you "throw" or velocity can be too low to mix the air.

    I think you need a pro to come look at it and recommend a solution when they replace the furnace and ac.
    1925 Two-Story Stucco Beaux Arts Neoclassical

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts