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  1. #14
    Join Date
    Apr 2002
    Posts
    11,808
    Originally posted by travisfl
    Originally posted by earthcondition
    Any suggestions?
    Measure the temperatures at your return and supply registers and (if you can get to it) at the return and supply plenums at the air handler, and post them here. If you have the condenser pressures from the tech's visit post them too, along with the outside temperature.
    Thats good advice, wouldn't hurt to check if the supply ducts are leaking in the attic.

    Must be some blinds to close when the sun is beating in.
    The way we build has a greater impact on our comfort, energy consumption and IAQ than any HVAC system we install.

    http://www.ductstrap.com/

  2. #15

    carnak

    all duct work is under my house. someone once posted if the supply duct is not the same size as the airhandler it could pose a problem or something to that nature, does that make since? also, I close blinds and doors to where sun is coming in. Temp. drop is anywhere from 18-20. when the techs last came it was spitting out about 51-54 degree air. that is cold! One more thing, the first vent off of the supply duct blows very forceful air and as you get further from the unit the vents blow less air. alot of homes I have been in blow the same velocity of air all through the house.
    The air starts getting colder about 7:30pm and by about 9pm the house is cold is ice and stays that way until about 10 or 10:30 am. then by about noon until 6pm the air doesnt seem as cold and that is when the temp. rises about 4 degrees above the setpoint.

  3. #16
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,758
    Check for air leaks in your duct work.
    Contractor locator map

    How-to-apply-for-Professional

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

  4. #17

    beenthere

    if I had leaks in the duct work it wouldnt matter what the temp was outside, I would still be losing air. My problem only happens when it gets above 90 then when it cools off it goes back to being ice cold.

  5. #18
    Join Date
    Jul 2004
    Location
    midwest
    Posts
    2,868
    You got 775 sq. ft. and a 2 ton A/C with a problem. Unless your insulation is poor or your windows are open a 2 ton unit should handle your house with ease. Like already suggested check for air leaks in the ducts.

    You are leaking air on the supply ducts
    Your return is drawing in hot air from someplace
    Your filter is dirty or to restrictive
    Ductwork not sized properly
    Dirty or plugged coil Techs are missing something on the A/C units charge

    One of these are your problem and we can't tell from here

  6. #19
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,633

    hotinsouth

    It's not nice to hijack a thread. But having said that, this is what you said from another thread:
    Originally posted by hotinthesouth
    I should be able to turn it down to 65 or less if I want to, other people do and their house feels like a meat locker and thats the way I want mine to.
    3 tons on a typical 2,000 square foot house will never get you what you want - not in the south, not in the west and not on Mars. The fact that the house creeps up to 78 by the end of the day doesn't surprise me one bit.

    You may yet have some problem that hasn't been figured out. Anything is possible. But having looked at you other threads I doubt it. I tend to believe it's more a question of incorrect expectations and false memories of what you think the system use to do. That's just my never to be humble opinion.

  7. #20
    Join Date
    May 2005
    Location
    washington state
    Posts
    9

    heat gain needed

    To size properly you need to do a heat gain. Windows and the direction they face is very important in the calc. their is no short cuts that work, just a properly done manual j worksheet.

  8. #21
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,633
    If you're speaking to earthcondition's problem Dan, then yes. In hotinthesouth's case I don't need a heat load calc to know that he'll never reach meat locker status with a 3 ton unit. :^)

  9. #22
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,758

    Re: beenthere

    Originally posted by hotinthesouth
    if I had leaks in the duct work it wouldnt matter what the temp was outside, I would still be losing air. My problem only happens when it gets above 90 then when it cools off it goes back to being ice cold.
    And this can be caused by a air leak.

    It may not be a large opening. It could be several small ones.

    Just large enough that it/they draws 100cfm in the return. Which would cause you to lose 6000btu's of cooling when the temp exceeds 90. But not hurt enough when the temp is less then 90.
    Contractor locator map

    How-to-apply-for-Professional

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

  10. #23

    irascible

    first off, I'm not hijacking anything. I have posted on here before and someone chimed in and said that it was the same problem that someone else had and for me to post under their thread so that is all I am doing. Second, I have no false memories. I know for a fact I could leave for work in the morning and leave my setpoint on 72 in the middle of august, return in the hottest part of the day and my temp. would be held on 72. If you feel a 3 ton unit will not cool a just under 2,000 sq. ft. home then would a 3 1/2 do the trick?

  11. #24
    Join Date
    Aug 2001
    Location
    forney texas
    Posts
    17,827
    I would say dirty condenser, clean it with water just to make sure.

  12. #25
    Join Date
    Jul 2000
    Location
    NW IL.
    Posts
    3,935

    Re: beenthere

    Originally posted by hotinthesouth
    if I had leaks in the duct work it wouldnt matter what the temp was outside, I would still be losing air. My problem only happens when it gets above 90 then when it cools off it goes back to being ice cold.

    Return air taken from wall studs could be pulling hot attic air into the system. As it gets hotter out the attic will get hotter, even hotter air being pulled into the return.

    Double check the attic insulation.

    If you have an infrared thermometer check the outside wall for hotspots. If you know someone with an infrared thermal imagery camera even better.

    Someone locally was being threatened that they didn't put the correct size system on a new construction in until the HVAC Contractor gave this ultimatum to the General Contractor "I'll hire an energy audit company do a blower test and check the house with a thermal infrared camera. If the house checks I'll pay for the audit and upsize the system. If the house doesn't you pay for the audit and make the corrections for insulation and leakage." Well the GC suddenly backs off and declares that he found that the incorrect amount of insulation was installed.

    Aircraft Mechanical Accessories Technician. The Air Force changed the job title to Air Craft Environmental Systems Technician. But I've decided I'll always be a Mech Acc.

  13. #26
    Join Date
    Jan 2004
    Posts
    144
    Check the evaporaror coil for air flow restrictions (dirty coil). Lower velocity from the restriction can cause a higher delta T, but not enough air flow to get to the furthest registers. This also could explain why the problem is worse this year than last year - return air not being properly filtered and dirt slowly building up on the evap coil.
    Licensing laws are tough, and it's about time.

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