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  1. #1

    Still having possible Cycling issues

    I would like to ask first if my unit is set for 2 cycles does that mean it will for sure cycle 2 times in 1 hour? Like 15 min 15 off 15 on 15 off? And it will kick on and off 2 time regardless. My installer said that is what it's set at right now. He was out of town when I called yesterday and will be back monday. He kept saying nothing is wrong with my system. I just keep getting really low on/off times. Here is what I recorded all day yesterday. The humidity droped when I turned the fan to auto and turned off my cooling droop about 1 pm. Sorry to keep asking you guys but does the system seem oversized? He said a load was done on the house and it required a 4 ton almost pushing a 5 ton system. I was going to have another company come out and do a load to see what they come up with. Do you guys think that would be a good idea? If it is oversized how hard would it be to get them to put a new unit in? Is there anything else they can do? He came out once and lower the fan speed due to a whistling sound and it sounded like a space shuttle launch when the system kicked on, which helped a lot. He said that he turned it down to 90%. I was reading that lowering the fan speed could help with times even more. How low would you want to go? Are there any options out there for me? Thanks Again. The system is only 1 month old.






    6/7/08

    8:00 am 64% humidity in the house Stat set at 76 degrees

    7:55 on 64%
    7:56 off - 1 min run time - 65%
    8:18 on - 22 min off time – 65%
    8:20 off – 2 min run time – 64%
    8:29 on – 9 min off time – 64%
    8:30 off – 1 min run time – 64%
    8:42 on – 12 min off time – 64%
    8:45 off – 3 min run time – 63%
    9:00 on 15 min off time – 64%
    9:02 off 2 min run time – 63%
    9:10 on 8 min off time – 63%
    9:13 off 3 min run time – 62%
    9:22 on 9 min off time – 62%
    9:23 off 1 min run time – 62 % OS temp 83
    9:35 on 12 min off time 61%
    9:39 off 4 min run time 60%
    9:45 on 6 min off time 60%
    9:47 off 2 min run time 60%
    9:53 on 6 min off time 60%
    9:56 off 3 min run time 59%
    10:18 on 22 min off time 63%
    10:27 off 9 min run time 61%
    10:43 on 16 min off time 61% OS temp 84
    10:54 off 11 min run time 60%
    11:08 on 14 min off time 61%
    11:19 off 11 min on time 59%
    11:34 on 15 min off time 61%
    11:44 off 11 min run time 59%
    12:00 on 16 min off time 61%
    12:10 off 10 min run time 59%
    12:24 on 14 min off time 59% OS temp89
    12:35 off 11 min run time 58%
    12:46 on 11 min off time 58%
    1:01 off 15 min run time 56%
    1:12 on 11 min off time 57%
    1:27 off 15 min run time 55%
    1:39 on 12 min off time 56%
    1:50 off 11 min run time 55%
    2:03 on 13 min off time 55%
    2:17 off 14 min run time 54%
    2:28 on 11 min off time 55%
    2:43 off 15 min run time 54% OS temp 91
    2:54 on 11 min off time 55%
    3:09 off 14 min run time 54%
    3:20 on 11 min off time 55%
    3:33 off 14 min run time 54%
    3:44 on 11 min off time 55%
    3:58 off 14 min run time 54%
    4:09 on 11 min off time 55% OS temp 92
    4:22 off 13 min run time 54%
    4:33 on 11 min off time 55%
    4:47 off 14 min run time 54%
    4:59 on 12 min off time 55%
    5:12 off 13 min run time 53%
    5:23 on 11 min off time 54%
    5:36 off 13 min run time 53%
    5:48 on 12 min off time 54%
    6:01 off 13 min run time 53%
    6:12 on 11 min off time 54%
    6:25 off 13 min run time 53%
    6:36 on 11 min off time 54%
    6:49 off 13 min run time 53%
    7:01 on 12 min off time 54%
    7:12 off 11 min run time 53%
    7:25 on 13 min off time 53%
    7:35 off 10 min run time 52% OS temp 89
    7:48 on 13 min off time 53%
    7:58 off 10 min run time 52%
    8:13 on 15 min off time 53%
    8:21 off 8 min run time 52%
    8:36 on 15 min off time 53%
    8:44 off 8 min run time 52%
    9:01 on 15 min off time 53%
    9:08 off 7 min on time 54%
    9:34 on 26 min off time 54%
    9:41 off 7 min run time 53%
    10:01 on 20 min off time 54%
    10:08 off 7 min run time 53%


    6-8-08

    0506 on 53%
    0509 off 3 min run time 53%
    0614 on 1 hr 15 min off 54%
    0616 off 2 min run time 54%
    0639 on 23 min off time 55%
    0648 off 9 min run time 54%
    0711 on 23 min off time 55%
    0719 off 8 min run time 53%
    0742 on 23 min off time 55%
    0748 off 6 min run time 53%

  2. #2
    Join Date
    Feb 2008
    Location
    Western NC
    Posts
    2,504
    anyone want to attempt to tackle this monster?????

    I'm gonna sit on the sidelines here and watch what happens
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  3. #3
    Join Date
    Aug 2007
    Location
    Clearwater, Fl
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    359
    Quote Originally Posted by iraqveteran View Post
    anyone want to attempt to tackle this monster?????

    I'm gonna sit on the sidelines here and watch what happens
    In the start it looked possibly oversized, but then my screen got all blurry and now I can't see anymore.

  4. #4
    Join Date
    Feb 2008
    Location
    Western NC
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    Quote Originally Posted by forcryinoutloud View Post
    In the start it looked possibly oversized, but then my screen got all blurry and now I can't see anymore.
    I hear ya.

    To the OP....you need a tech to come take a look......on/off times tell us nothing without knowing the equipment, stat, ID/OD temps, pressures, etc....


    Oh, and forcryinoutloud....I just wanna say...........

    Thats a great screen name. Fits this place perfectly.
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  5. #5
    Join Date
    Aug 2007
    Location
    Clearwater, Fl
    Posts
    359
    Quote Originally Posted by iraqveteran View Post
    I hear ya.

    To the OP....you need a tech to come take a look......on/off times tell us nothing without knowing the equipment, stat, ID/OD temps, pressures, etc....


    Oh, and forcryinoutloud....I just wanna say...........

    Thats a great screen name. Fits this place perfectly.
    Have used that line several times when dealing with new guys just out of school. Usually something along the lines of, For cryin out loud, didn't they teach you how to hook up your guages properly.

    We must have terrible instructors in this area, more than one FNG didn't know how to hook up the guages properly.

  6. #6
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,390

    Hmm Change out to smaller 2-stage unit maybe in order

    Quote Originally Posted by rickytz7111 View Post

    My installer said that is what it's set at right now. He was out of town when I called yesterday and will be back monday.

    He kept saying nothing is wrong with my system. I just keep getting really low on/off times.

    ... and it required a 4 ton almost pushing a 5 ton system.

    If it is oversized how hard would it be to get them to put a new unit in? The system is only 1 month old.

    6/7/08
    8:00 am 64% humidity in the house Stat set at 76 degrees

    7:55 on 64%
    7:56 off - 1 min run time - 65%
    8:18 on - 22 min off time – 65%
    8:20 off – 2 min run time – 64%

    6-8-08

    0648 off 9 min run time 54%
    0711 on 23 min off time 55%
    0719 off 8 min run time 53%
    0742 on 23 min off time 55%
    0748 off 6 min run time 53%
    It appears to be significantly oversized.

    Ask them !

    Otherwise, it is likely time to install a whole house dehumidifier.
    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

  7. #7
    The outdoor temps are next to the humidity readings every so often. The hottest it got that day was 92 degrees. I had the house set at 76 degrees all day long the system is a 4 ton AS allegiance 14. I have gas for heat. The stat is a AS family 400. The tech has been out twice and says it's fine. I just don't think he wants to hear the unit is to big for the house. I asked him that and he got really deffensive. He said it's border on needing a 5 ton system. Could I contact the Corp. Office of AS in Tyler Tx and see if they can do anything about it?

  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,601
    Seems oversized.

    Hearing only your side of the story. If this contractor is saying your house almost came out to a 5 ton, and with your current run times and humidity. He either entered data into the load program wrong, or didn't do one and is trying to CHA.

    Ask to see the load calcs.

    You can pay a 50 dollar fee and do your own.
    http://hvaccomputer.com/talkref.asp

    My boss managed to oversize one a few years back. We took it out 4 weeks later and put the right sized one in.(he fell for the I'm adding an addition routine)
    It was oversized by 1 ton. Short run times, and high humidity, until we put the right sized one in.
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  9. #9
    Thanks beenthere is that software hard to use? I'm very ignorant when it comes to duct sizing and all that stuff. I can count windows and color of shingles and stuff like that. I was going to call another company and have them do a load. Then I would have some hard proof of it being oversized. Are there any other options as far as lowering fan speed a little more or do you just feel it is oversized? I'm going to go ask a neighbor down the road. It looks like we have the same house design to see if he is having the same problems i'm having.

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,601
    The program is easy to use. You don't have to worry about duct sizing.
    Enter the values for teh wall insulation, sq ft, the direction they face, etc.
    You may find it hard to find another company local to do a load calc, let alone do one now when they are busy with calls and replacements.
    But it never hurts to look.

    Slowing the blower can only help so much. And when its only 2 or so degrees hotter out then your set point on the stat, it will still short cycle. And you will still have high humidity.
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  11. #11
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304
    A house in Tyler is not seeing the full effect of summer yet. Isn't Tyler about 50 miles east of Dallas TX? So I am wondering whether measuring runtimes is the right thing to do when it's not a typical summer day. Certainly I wonder what you can learn from the nighttime measurements. I am a homeowner in S.Texas who has used runtime data logging as an aid to estimate sizing -- I also ran Hvac-Calc and didn't completely trust my results due to inexperience. What I learned was through an entire summer, there was no single hour where I saw more than 85% runtime. With that info, and talking it over with my AC contractor, we together decided to downsize a half ton. Just wanted to tell you what runtime measurements mean to me.

    Your contractor may be entirely sincere when he insists 5.0 tons is the right size, it will be a project of diplomacy for you and him to reach agreement. You might ask him what are the actual numbers for sensible (thermometer) and latent (humidity) heat gain. The sizing answer might be in his numbers, or possibly his has erred in applying them. You might ask him what he used for indoor and outdoor design temperatures, there is possibility for error and disagreement there. He might assume you want 68F indoors when it is 105F outside. He might be trying to defend your ability to have a July 4 party with many people going in and out through the doors.

    Good luck finding another pro to do load calcs for you, if you find someone willing then treat them well. I have had a devil of a time finding that in my locale. I strongly suggest downloading Hvac-calc software from this site, and running it yourself. It's not too hard, and with the printed reports you and another contractor can discuss points where you might not exactly agree.

    My experience as a customer tells me that sizing is an area of real controversy, some around here still swear by 500 sqft/ton. I have heard experienced AC pros tell me that Manual J comes up with big differences depending on who does it. I say this to illustrate perceptions, not that I believe the disagreement was legitimate. But you gotta deal with the people actually doing business where you live.

    The idea of a whole house dehumidifier is also a very good one. I have a large Thermastor stand-alone and it can help your indoor humidity a lot. Nothing can do as good a job in humid spring and fall seasons, when an AC has much less call for cooling.

    Hope this helps -- Pstu

  12. #12
    Join Date
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    Location
    Lancaster PA
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    Quote Originally Posted by pstu View Post
    A house in Tyler is not seeing the full effect of summer yet. Isn't Tyler about 50 miles east of Dallas TX? So I am wondering whether measuring runtimes is the right thing to do when it's not a typical summer day.

    Manual J list Tyler as a 97* design temp. So he's at 94* of listed design temp, and only running about a 55% duty cycle.

    If you were to design to 105*, he's 87% of design, and still only running a 55% duty cycle.




    Your contractor may be entirely sincere when he insists 5.0 tons is the right size,
    I think if yopu check, you'll find he has a 4 ton A/C. And teh contractor is trying ot say his house could use a 5 ton, trying to justify the 4 ton sizing.

    You might ask him what he used for indoor and outdoor design temperatures, there is possibility for error and disagreement there. He might assume you want 68F indoors when it is 105F outside. He might be trying to defend your ability to have a July 4 party with many people going in and out through the doors.
    And if designed for 68* ID at 105* OD, you would need to keep the stat at 68* to feel cool on the lower 90* days. And the contractor would have already told him to set his stat to 68 as designed.

    The idea of a whole house dehumidifier is also a very good one. I have a large Thermastor stand-alone and it can help your indoor humidity a lot. Nothing can do as good a job in humid spring and fall seasons, when an AC has much less call for cooling.

    Hope this helps -- Pstu
    I have nothing against a whole house dehumidifier. But having to buy one because your new A/C is over sized isn't right.
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  13. #13
    I have found 2 companies that will do a load cal for me. I spoke with the general manager of a very respectible company in town. He also said that everything sounds fine due to my low humidity rate. He says anything close to 55% is great in Little Rock Arkansas. I told him it just seems like it kicks off and on quit a bit. I just want to get the best performance out of the system that I can.

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