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A/C not cool enough

mrfixitusa | Posted in General Discussion on June 22, 2008 11:59am

Bill on days like today when the temp is 90 degree and hotter outside
my A/C runs non-stop

It runs continuously to cool the house to 77 or 78 degrees

Is this par for the course or is something not working properly

My A/C unit (exterior unit) is only one year old

Thanks for your input and suggestions

Reply

Replies

  1. junkhound | Jun 23, 2008 12:47am | #1

    Did it cool you last year?

    Is the unit sized properly? 

    Is the filter clean?

    Is the condensor grill clean, or plugged with cottonwood 'snow'?

    Do you use it as a HP in the winter, how was it then?

    Did you just put in a new condensor last year, and not balance the system?

    Who installed it?   Was a new liquid line dryer installed?

    TXV or orifice, if TXV, what was the subcool, if orifice, what was the superheat?  (from what Ive read, 30% or more of "professional" HVAC techs cant answer that question)

    Ya might have a leak. 

    Ya might have water in the system and ice in the orifice or TXV.

    Can you run a suction and high side pressure test yourself/  What are the pressures?

    If you cant run pressure tests (supposed to have an EPA license for R22), what are the temperatures of the liquid line and the suction line?

     

    etc.......

    1. mrfixitusa | Jun 23, 2008 01:20am | #5

      Yes it did better last yearI'm worrried about a month from now when we get to 100 degreesI don't know anything about the A/C unit except that it's a Coleman and the technician connected it and did all of the installationAir supplies are in crawl space and return air duct is in hot attic.Thanks to everyone for their responses and input

      1. USAnigel | Jun 23, 2008 01:46am | #6

        First thing is cool air coming out of the ducts? Drill a hole or find a gap to poke a temp probe in before the evaporator coil and check temp after the coil. Whats the temp drop between the two? If its up  to spec then go to lowes and rent the insulation blower and add to the attic. Make sure to add over the duct work.

        Don't look for a bigger "engine", reduce the load on the one you have!

      2. User avater
        BillHartmann | Jun 23, 2008 05:09am | #7

        Other than what every one else said with the return duct in the attic if anything has come loose it will kill the performance..
        .
        A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

  2. DanH | Jun 23, 2008 12:48am | #2

    Unit could be mischarged, could be undersized, could be defective.  Could be you just need to keep the door shut more.

    You need to get the unit checked out.

    It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
  3. junkhound | Jun 23, 2008 12:57am | #3

    One more: 

    Is it a Lennox?  There are apparently service bulletins out that unless teflon tape is used on the valve caps and reeefed down hard, 2006 Lennox condensors leak. 

    Also, since it is first summer after your first winter, is the unit above ground ice level - lower end of the coils being in ice can crack a braze or pipe.. 

  4. renosteinke | Jun 23, 2008 01:14am | #4

    There are a lot of possibilities ... but the first thing that stands out is that your are trying to maintain a cooler temperature than the handbooks assume you will want. As a result, your unit might be undersized.
    We went through this last year with a poster ... who never mentioned the 'little detail' that he liked to set his at 65F.

    Yet, it's been my experience that AC units are usually oversized. Short cycling - the AC starting up more than 4 times an hour - is actually a worse situation than continuous operation.

    The most common causes of poor AC performance are the simplest ones .... something blocking air flow over the condenser coils, evaporator coils iced over, poor duct design (restricting air flow), poor duct placement (like through a hot attic), poor duct installation (air leaks).

    It's this troubleshooting process that separated the pro from the hack. Just installing a bigger unit isn't likely to solve the problem.

  5. alwaysoverbudget | Jun 23, 2008 06:46am | #8

    well since i'm feeling the same heat/humidity i throw in 2 cents worth.

    first are you leaving the air on all the time? if you shut it down while at work,then kick it on it will have a tough time keeping up.

    check the air filter

    make sure the outside unit is clean,the cottonwood is starting to fly

    thats the easy things. what size unit did they put in for you? lot of guys would maybe do a 2.5 ton in your house.i don't think thats enough but 3t should catch it.understand i don't know how to do load calcs etc. thats just what i see in my houses. 1000sf 2.5 up to 1200 3t 1200 to 1600 3.5

    heres something that just hit me ,didn't you put in a new fan motor this winter?if so are both speeds working?air blows alot more than heat.

    anyway if the size is about right,if it's running all the time do you see any ice forming right at the a coil box?thats a indication that it's low on freon also.

    lastly is it still under warraty?call them.

    if you don't have a set of gauges let me know i'll run over in the eve and stick mine on. we can tell pretty quick if it's low  larry

    if a man speaks in the forest,and there's not a woman to hear him,is he still wrong?

    1. mrfixitusa | Jun 26, 2008 05:06am | #9

      Larry thanks for your infoI've put a call in to the company who installed the A/C unitI've got my blower fan running on high speed and the outside unit is
      cleanI spray it (on the outside) once a week or so and kind of clean it upI probably should take the top cover and spray water from inside to outside but I hate trying to take it apart and put it back togetherToday I set the Thermostat on 75 degrees and the A/C ran all day and kept the house at 76 or 77 with non stop operationI drove by the bank this afternoon and it said temp is 98 degrees so
      I'm probably doing okay all things consideredIf i was going to stay in this house I think I would move the return air and eliminate the duct running through the atticThis house only has one return air duct for the entire house and that's the way it has been for 50 yearsThanks again

      1. User avater
        BillHartmann | Jun 26, 2008 07:34am | #10

        Bank thermometers are not to be trusted. Often the temp sensor is not properly shield.Weather underground show the high at ICT as 91 and 90 at Jabara. Ans 91 at IAB..
        .
        A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

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