Results 1 to 8 of 8
  1. #1
    Join Date
    Dec 2006
    Location
    Texas
    Posts
    16

    Oversized HVAC to supply blower

    Is this correct? My HVAC contractor agreed that our house only needed a 3 ton unit (3150sf, SIP walls and roof, energy efficient everything.) However, he says we have to have a 4 ton unit in order to match the blower necessary for the size of the house. Is this correct? He says it doesn't matter if the unit is oversized since we have a Carrier Infinity 19 and it will only run on low unless really needed. Now that it is installed, I have never seen the unit run more than 6 minutes even on a hot day. I am not sure if I can tell the difference by hearing but I cannot say the unit has ever sounded like it was running on 2 different speeds.
    Thanks

  2. #2
    Join Date
    Jun 2008
    Location
    Lancaster Pennsylvania
    Posts
    60
    Did he Reuse your exsisting ductwork or did he modify it?

  3. #3
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,754
    if it only needed 3 tons why would it need a 4 ton blower..

  4. #4
    Join Date
    Dec 2006
    Location
    Texas
    Posts
    16
    He said the 4 ton blower would not be able to supply enough air for the 3150sf of the home. This was new construction so sizing ducts was up to him.

  5. #5
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,754
    he goofed.

    if the load was only 3 tons the house only needed 3 tons worth of air flow.


    now you have an oversized system that probably will not run enough to dehumidify.

  6. #6
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,334
    So now you have a 4 ton unit. Running in first stage, at a reduced air flow.
    That is about the same air flow as you would have got with the 3 ton system.

    He goofed, or just doesn't know any better.

    Do a search for member "paul42".
    He has a 4000 sq ft house, with a 2 ton system.
    Contractor locator map

    How-to-apply-for-Professional

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

  7. #7
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    Hmmm. Day late and a dollar short. You should have visited this website before the installation. We'd have told you then not to accept anything but a Manual 'J', Manual 'D' and Manual 'S' calculation, layout and equipment selection. Anything less is guesswork and bush league. If the house called for 3-tons, then it should have 3-tons. If it called for 3.5-tons and you got a 4-ton that runs 6-minutes on the hottest day, I'd say someones cacluations are suspect. Ask for the load calcs. Seems like the low ball system even if you paid for top drawer.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  8. #8
    Join Date
    Dec 2007
    Location
    Cedar Grove, Wi-Sheboygan
    Posts
    1,582
    Was this unit recently installed or is the first year over and done with ? If your still within your first 6months-1yr tell him the problems yoru having and ask him to change it out with the proper size equipment.

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