Page 2 of 2 FirstFirst 12
Results 14 to 25 of 25
  1. #14
    Join Date
    May 2000
    Location
    Rochester, NY, USA
    Posts
    14,302
    oddly enough I JUST fixed a system with a similar problem in split level home.

    lets see if I can describe the problem, what I did to fix the problem will be in RED

    Original Equipment: 2½ton Whirlpool approximately 25-30YOA, air handler in the lower attic, with a remote box plenum in the upper attic. the upper attic handled the 3 bedrooms and a full bath. lower plenum went to the living room, dining room and kitchen. (all supply runs are R-4 insulated flex)
    Supply to dining room=8"--increase to 10"
    supply to dinning room and kitchen=8" split to two 6"--added two separate 8" runs
    supply to upper remote box plenum=10"--added a 12" supply to the remote box plenum---->Off the remote box plenum
    supply to Bath and bed rm#1=8" split to 6"--remove the 8" and added two separate 6" runs
    Bed rm#2 remained one 6"
    Bed rm #3 = 8" split to two 6" -- removed 8" and added two separate 6" runs
    (all added flex are R-8 insulated)

    Return flex is 16", centrally located at the top of the stairs---left it as is


    Customer complaint was there was almost no air coming from the registers, and the a/c was toast

    I installed a Rheem Variable speed 2½ton condenser with a 2½-3 ton air handler. increased the supply runs as stated.

    Blatant bragging

    customer unbelievably happy, said the house has never cooled this well in the 3 years they have owned the home. They said "we have never felt so much air coming from the registers"

    The point is, if you have one room with little to no air flow, the only fix is to increase the duct and increase air flow to that room.

    Increasing the size of the equipment won't help you out unless the system was undersized to start with.
    The Last four letters


    American = I Can, Republican = I Can, Democrats = Rats


    any questions

  2. #15
    Join Date
    Aug 2011
    Posts
    568

    Cool

    Quote Originally Posted by warm View Post


    you can not push 1800/2000 cfm throught ductwork desizing for 1200/1400cfm
    question is this, with out seeing the duct work, how do you know it's sized for 1200-1400 cfm? the h/o hasn't given us pic.sizes, etc!

  3. #16
    Join Date
    May 2000
    Location
    Rochester, NY, USA
    Posts
    14,302
    Quote Originally Posted by MM#7 View Post
    question is this, with out seeing the duct work, how do you know it's sized for 1200-1400 cfm? the h/o hasn't given us pic.sizes, etc!
    true, my point is, increasing the size of the equipment may not be the answer.

    I suppose had the "reputable" contractor done the math, he could have fixed the problem, it may have cost more to correct an inefficient duct system, but at least it would have worked
    The Last four letters


    American = I Can, Republican = I Can, Democrats = Rats


    any questions

  4. #17
    Join Date
    Aug 2011
    Posts
    568

    Hmm

    Quote Originally Posted by jmac00 View Post
    true, my point is, increasing the size of the equipment may not be the answer.

    I suppose had the "reputable" contractor done the math, he could have fixed the problem, it may have cost more to correct an inefficient duct system, but at least it would have worked
    i understand, problem with this board is a lot of times people speculate on answers w/o pictures,accurate assesment of actual h/o problems, what a h/o is willing to do, open walls,spend $, and so forth. its been my exp. that once a house has a system put in, to change the duct system becomes quite expensive, so you have a contractor, comes up with a compromise based on financial considerations. moving and modifying duct can be exp. especially in basements,hard duct returns,and opening up walls,( patching/ painting) in a attic less exp. do to mostly changing flex,

  5. #18
    Join Date
    Mar 2007
    Location
    Orange County NY
    Posts
    212
    The simple fix is to add another duct run to the area to increase the cfm available to the room.
    Do a manual J on the room first to find out what is required.

  6. #19
    Join Date
    May 2000
    Location
    Rochester, NY, USA
    Posts
    14,302
    Quote Originally Posted by MM#7 View Post
    i understand, problem with this board is a lot of times people speculate on answers w/o pictures,accurate assesment of actual h/o problems, what a h/o is willing to do, open walls,spend $, and so forth. its been my exp. that once a house has a system put in, to change the duct system becomes quite expensive, so you have a contractor, comes up with a compromise based on financial considerations. moving and modifying duct can be exp. especially in basements,hard duct returns,and opening up walls,( patching/ painting) in a attic less exp. do to mostly changing flex,

    exactly, the job I just got done with was all flex, so it was easy and fairly inexpensive to correct. replacing drywall is a whole other problem...screw that

    The Last four letters


    American = I Can, Republican = I Can, Democrats = Rats


    any questions

  7. #20
    Join Date
    Aug 2011
    Posts
    568
    Quote Originally Posted by jmac00 View Post
    exactly, the job I just got done with was all flex, so it was easy and fairly inexpensive to correct. replacing drywall is a whole other problem...screw that

    ok amigo!

  8. #21
    Join Date
    Aug 2011
    Posts
    568

    Cool

    Quote Originally Posted by jackpiner View Post
    The simple fix is to add another duct run to the area to increase the cfm available to the room.
    Do a manual J on the room first to find out what is required.
    sounds good goshen!

  9. #22
    Join Date
    Jan 2005
    Posts
    113
    how is the 5 ton furnace gonna work in the winter? a furnace with a 5 ton blower will put out more btu's than needed and will short cycle. a 5 ton blower will move the air to quickly across your coil the air coming out will not be as cold.

  10. #23
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,286

    Hmm

    Quote Originally Posted by sir fix alot View Post
    a furnace with a 5 ton blower will put out more btu's than needed and will short cycle. .



    A furnace with more air flow provides air at a lower heat rise.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  11. #24
    Join Date
    Jan 2005
    Posts
    113
    my point was a furnace with a 5 ton blower would have more burner"s / btu out put than needed curently has a 3.5 ton furnace blower could be 90 to 110,ooo btu . furnace sized with a 5 ton blower would be quessing 125- 175,000 btu.

  12. #25
    Join Date
    Aug 2011
    Posts
    568

    Confused

    Quote Originally Posted by sir fix alot View Post
    my point was a furnace with a 5 ton blower would have more burner"s / btu out put than needed curently has a 3.5 ton furnace blower could be 90 to 110,ooo btu . furnace sized with a 5 ton blower would be quessing 125- 175,000 btu.
    i see what your saying, the h/o is basically looking for a less expensive fix, do to the $ needed to possibly redo duct work,patch walls,etc. it's kinda like years ago, i had a chevy vega, me and my buddies modifired it and put a 350 v8 engine in it, thing went 0-60 like a F@@@in rocket, one draw back, put so much torgue on the frame, it twisted it! bottom line for every action you get a reaction! there's 3 ways to approach a problem, the right way, the wrong way, don't do any thing and live with it! that's a dilemma in life!

Page 2 of 2 FirstFirst 12

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