Page 1 of 2 12 LastLast
Results 1 to 13 of 14
  1. #1
    Join Date
    Apr 2012
    Posts
    7

    Little more help, please...

    Hello, I have read through this and a few other threads on the topic and have learned quite a bit, but still have a couple questions:

    I live in Arizona and the fall/winter months have temps in the 80s or 70s during the day and down to the 60s (sometimes 50s) at night. Basically, with some minor assistance from the A/C unit during the day, the temp in our house stays at a comfortable 75-78 degrees. The issue I have is that the unit seems to cycle excessively during non-warm hours (evenings/nights/mornings), when the temperature is already sitting comfortably in the range we have set. Our house is not big and with new air being blown into the spaces, they almost act to cool the room and are definitely uncomfortable if you happen to be near one of the registers. I looked at the T-stat manual and our T-stat and found that our CPH was set at 6. I reduced this to the "d" setting which in the manual tells me is "cycles per hour limit defeated." Can anyone help me understand what this setting really means? Since I made this change, I haven't noticed it cycling as much, but I'm not sure I know for sure what I have really done to the system.

    As I mentioned, I am just looking to reduce the frequency and duration of the air cycles, especially when the temperature is within range. (Also, not sure if it is related, but the deadband setting is currently at 2 degrees).

    Any further education on this topic would be much appreciated.

    Thanks!

  2. #2
    Join Date
    Apr 2012
    Posts
    7

    Little more help, please...

    ***I already posted this question on another thread, but then noticed that that thread was two years older than this one, so I am re-posting here. Please let me know if that is a violation of any forum rules and if so, my apologies, and where would be the best place to post my question?***


    Hello, I have read through this and a few other threads on the topic and have learned quite a bit, but still have a couple questions:

    I live in Arizona and the fall/winter months have temps in the 80s or 70s during the day and down to the 60s (sometimes 50s) at night. Basically, with some minor assistance from the A/C unit during the day, the temp in our house stays at a comfortable 75-78 degrees. The issue I have is that the unit seems to cycle excessively during non-warm hours (evenings/nights/mornings), when the temperature is already sitting comfortably in the range we have set. Our house is not big and with new air being blown into the spaces, they almost act to cool the room and are definitely uncomfortable if you happen to be near one of the registers. I looked at the T-stat manual and our T-stat and found that our CPH was set at 6. I reduced this to the "d" setting which in the manual tells me is "cycles per hour limit defeated." Can anyone help me understand what this setting really means? Since I made this change, I haven't noticed it cycling as much, but I'm not sure I know for sure what I have really done to the system.

    As I mentioned, I am just looking to reduce the frequency and duration of the air cycles, especially when the temperature is within range. (Also, not sure if it is related, but the deadband setting is currently at 2 degrees).

    Any further education on this topic would be much appreciated.

    Thanks!

  3. #3
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    24,947

  4. #4
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    5,990
    A little more help might be provided based on Your Specific Thermostat.
    You have the manual but we can't read it.

    What is the thermostat Model Number and the Manufacturer?
    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
    Apr 2012
    Posts
    7
    Thank you jpsmith for starting a new thread for me. Dan, as best I can tell from the thermostat, it is a Totaline Programmable Thermostat, and the only number I can find on it, which I'm guessing might be the part number is: "P/N 0441." When looking for the manual, this is the closest one I have found:

    http://www.totaline.com/dl/P374-1000...Thermostat.pdf

  6. #6
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    5,990
    Quote Originally Posted by ezdizzy View Post
    Thank you jpsmith for starting a new thread for me. Dan, as best I can tell from the thermostat, it is a Totaline Programmable Thermostat, and the only number I can find on it, which I'm guessing might be the part number is: "P/N 0441." When looking for the manual, this is the closest one I have found:

    http://www.totaline.com/dl/P374-1000...Thermostat.pdf
    Sure would be nice to have the Totaline Thermostat 0441 manual.

    Plus, I am stuck on no specific definition of Defeated [ manual, Pages 12-13], just as you are.

    I would set CPH =2.
    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
    Join Date
    Apr 2012
    Posts
    7
    Dan--

    Thanks for taking a look. I agree, I wish I had the original manual. I am actually renting the residence and have requested the manual from the owner, but they don't have it.

    Based on some other thread comments I've read in this forum (I think one was by jpsmith1cm), woudn't a CPH setting of 2 cause the fan to run for 30 minutes and then sit idle for thirty minutes? I really don't know much about the cycle settings, so maybe I am remembering that wrong, but it seems like that might not be what I am trying to accomplish....? (i.e. having less air blowing when the temp is in range). Please correct me if I am misunderstanding the meaning of the CPH setting.

    And if anyone else has any input on what the "Defeated" term is referring to, please chime in.

    Thanks again.

  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,776
    As Dan said. Set CPH to 2. It will attempt to run 15 minutes, stay off 15 minutes. Will vary by outdoor temp.
    Contractor locator map

    How-to-apply-for-Professional

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

  9. #9
    Join Date
    Apr 2012
    Posts
    7
    So let's assume I have the thermostat set to cool at 78 and heat at 72. If the outdoor temp is, say, 68, and the indoor temp is reading at 76, will it still run for the full 15 minutes, twice an hour? I don't know if I understand what you mean when you say it will "attempt" to run for 15 minutes...? Again, I am trying to limit the time that the system spends blowing air when the temperature is within the set range, so having it run for 15 minutes twice an hour kind of defeats that goal, right?

    Thanks again for your patience and help!

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,776
    No. Since there wouldn't be a call for heat or cool. it won't do anything.

    It will attempt to do 2 CPH. but can only do that when the house is gaining or losing heat. When the indoor temp is not above the cooling set point or below the heating set point, it won't run the system.
    Contractor locator map

    How-to-apply-for-Professional

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

  11. #11
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    5,990
    Quote Originally Posted by ezdizzy View Post
    So let's assume I have the thermostat set to cool at 78 and heat at 72. If the outdoor temp is, say, _82_, and the indoor temp is reading _78_,
    The A/C will runs for about 12 minutes and be off for 32 minutes. ... W.A.G. [ depending on time_of_day ]

    + with Relative Humidity at 54%, you'll react to _ Your auto comfort sensor _ by adjusting the thermostat to 76'F.
    Then there will be one cycle at about 64 minutes ON, bringing the relative humidity down to 46% in ~14 minutes and temperature decrease 2'F in following 50 minutes or so.
    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

  12. #12
    Join Date
    Apr 2012
    Posts
    7
    So it sounds like in the summer months, when the system is working much harder, it would be best to leave the CPH setting at 6, then drop to 2 during the months when it is hardly needed (winter months)? Sound right? I can't imagine having the A/C run for 50 mins at a time would be good, but again, not my area of expertise.

    Also, did anyone else have any input on the "defeated" term? I currently have the system set to "d" which according to the manual means "cycles per hour limit defeated." When on this setting, the fan will still kick on occasionally, even when the actual temp reading is within the cooling and heating set points....

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,776
    6 CPH for cooling is way too much. Set it for 3 or 2. longer run times are better for a compressor then lots of cycling on and off.
    Contractor locator map

    How-to-apply-for-Professional

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

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event