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  1. #1

    Problems with Goodman Gms8 60k btu/ Possible Sizing Issues?

    Not too sure if the problem with my furnace is it being undersized or an issue with furnace. The furnace is a brand new Goodman GMS8 80% 60000 btu in a 926 bungalow 9ft walls, ceilings are insulated, walls are not insulated, and 4 inch rectangle high supply duct(house was build in 20s). The problem that i am finding is that it is producing luke warm air and the furnace continues to run and run. I tried to adjust blower speed but even with setting set on high it will not even heat above 50. The supply duct on top of the furnace seems to be warm but not hot. Any ideas on why the furnace is only producing luke warm air and not hot air? And will this furnace even be enough to satisfy this size house requirements? I know ive seen some newer construction houses larger with a 60k looking for some imput.

    Thanks,
    Grant

  2. #2
    Join Date
    Dec 2005
    Location
    Cincinnati, Oh
    Posts
    4,663
    Quote Originally Posted by grant087 View Post
    Not too sure if the problem with my furnace is it being undersized or an issue with furnace. The furnace is a brand new Goodman GMS8 80% 60000 btu in a 926 bungalow 9ft walls, ceilings are insulated, walls are not insulated, and 4 inch rectangle high supply duct(house was build in 20s). The problem that i am finding is that it is producing luke warm air and the furnace continues to run and run. I tried to adjust blower speed but even with setting set on high it will not even heat above 50. The supply duct on top of the furnace seems to be warm but not hot. Any ideas on why the furnace is only producing luke warm air and not hot air? And will this furnace even be enough to satisfy this size house requirements? I know ive seen some newer construction houses larger with a 60k looking for some imput.

    Thanks,
    Grant
    You messed with the blower speeds?
    Wrong call.

    Call a professional about this one. Messing with blower speeds without knowing what your doing can cause you to crack your heat exchanger, or cause condensation in the flue, ruining your chimney.

    Either way, you could need a new furnace if you continue. Bumping up the speed could cause you to need a new furnace AND chimney.
    "Better tell the sandman to stay away, because we're gonna be workin on this one all night."

    "Dude, you need more than 2 wires to a condenser to run a 2 stage heatpump."

    "Just get it done son."

    Dad adjusted

  3. #3
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,820
    Call the installing contractor back, its under warranty if it was just installed.
    Contractor locator map

    How-to-apply-for-Professional

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

  4. #4
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,001

    Furnace Performance ?????????

    Quote Originally Posted by grant087 View Post

    Not too sure if the problem with my furnace is it being undersized or an issue with furnace.
    The furnace is a brand new Goodman GMS8 80% 60000 btu in a 926 bungalow 9ft walls,
    ceilings are insulated, walls are not insulated, and 4 inch rectangle high supply duct
    (house was build in 20s).
    The problem that i am finding is that it is producing luke warm air and the furnace continues to run and run.

    I tried to adjust blower speed but even with setting set on high it will not even heat above 50. The supply duct on top of the furnace seems to be warm but not hot.

    Any ideas on why the furnace is only producing luke warm air and not hot air?
    And will this furnace even be enough to satisfy this size house requirements?
    I know ive seen some newer construction houses larger with a 60k looking for some input.

    Thanks,
    Grant
    Unless your house is as leaky as leaving he windows open, 60,000 BTU/Hr is likely adequate.

    4" high duct does not seem to be a good situation
    IF you are referring to the main duct (header).

    _ 4" x 20" = 80 sq. inch = ~ 0.6 sq feet
    which might handle 600 CFM / 1,000 FPM

    50,000 BTU/Hr = ~ 70'F temperature rise.
    ------------------------------------------------

    Simplified Heat Load will be calculated based on
    following Parameters
    Ceiling R-20 926 Sq. Feet
    Floors R-6 926 Sq. Feet
    Walls R-3 900 Sq. Feet
    Windows U-1 100 Sq. Feet
    Infiltration 1 ACH ( 0.2 Tight, 0.6 Typical )
    No basement

    as a Worst Case ( W.A.G.)
    You will need to adjust values to match your actual situation.
    ....................... ___________ ..................... _____.................
    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

  5. #5
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,001
    926 Sq. Foot / 1920's Residence

    Ceiling______ 2,800 BTU/HR
    Wall _______ 18,000
    Window_____ 6,000
    Floor _______ 9,300
    Infiltration___ 10,700
    _______
    Total _______ 46,800 at 10'F
    dT _______ 60 dT
    Loss per degree __ 780 BTU per Hour / 'F
    50' - 10'F _______ 40 dT
    _______ 31,200 BTU/Hr

    1,400 Therms per year in 6,000 Heating Degree Day climate
    ____
    Location was NOT provided by OP.
    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

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