Results 1 to 6 of 6
  1. #1
    Join Date
    May 2005
    Posts
    74

    Hmm

    Many know that I am finishing building my addition over the garage. Additional 650 square feet - extended both the master bedroom and the kids room. What the HVAC guy did was take the supply ducts off the MBR and made sort of like a main trunk line into the addition. Then, he created branches off that main extended trunk line and fed the new parts of both rooms. I felt the pressure coming out of the old supplies vents today - felt normal, fairly strong flow of air coming out of them. Then, I felt the air coming out of the new supply vents - much lower pressure. Is that normal or should they be the same pressure as the old ones?

    I'm cooling the space now but its nightime and I'll see if the entire room is cool in the morning.

  2. #2
    Join Date
    Jul 2002
    Location
    Zelienople, Pa
    Posts
    2,965
    If the system wasn't oversized to begin with, you will have problems.
    600 square ft. is qite a bit of a new load.
    Where do you think the extra airflow is coming from?
    Its coming from the vents that it used to supply.
    How tall are you Private???!!!!

  3. #3
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    If the old sytem had extra capacity,and th duct was sized and installed correctly,you'll be fine.

    An addition almost always makes an old exterior wall/window an interior one,which reduces the load in that room.

  4. #4
    Was the extended ducts from the MBR the ones originally dedicated for that room? If tey were 6 inch round ducts they will only handle the flow for 1 register if they extended them to now handle additional flow thats a problem.

  5. #5
    Join Date
    Mar 2004
    Location
    Gone
    Posts
    5,340
    When did the size of a duct start dictating how many registers it can feed?

  6. #6
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    5,031
    Originally posted by mxylplik2
    Many know that I am finishing building my addition over the garage. Additional 650 square feet - extended both the master bedroom and the kids room. What the HVAC guy did was take the supply ducts off the MBR and made sort of like a main trunk line into the addition. Then, he created branches off that main extended trunk line and fed the new parts of both rooms. I felt the pressure coming out of the old supplies vents today - felt normal, fairly strong flow of air coming out of them. Then, I felt the air coming out of the new supply vents - much lower pressure. Is that normal or should they be the same pressure as the old ones?

    I'm cooling the space now but its nightime and I'll see if the entire room is cool in the morning.
    There should have been equal or larger capacity "Return Air" ducting from those rooms back to the blower.

    http://www.udarrell.com/proper_cfm_b...g_systems.html


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