Need some serious hvac advice!

Discussion in 'The Okie Corral' started by Foxterriermom, Jul 13, 2020.

  1. Foxterriermom

    Foxterriermom No place like home

    Messages:
    7,079
    Likes Received:
    14,553
    Joined:
    Mar 2, 2009
    Location:
    Lone Star State
    I am hoping that some knowledgeable GTers can offer some helpful information and advice to me.

    Last month I had a 16 year old 3 ton Payne hvac system replaced that had a Freon leak in the evaporator coil and a blower was beginning to struggle. I decided to bite the bullet and replace the system before this one gave out. My heating/cooling square footage is 1470.

    It was replaced with an American Standard 3 ton system with a variable speed air handler. Immediately after installation, I began to notice that the system was short cycling running perhaps for 5-8 minutes and then restarting again within 4-8 minutes. The installer said this shouldn’t be happening, so he sent his men back out to relocate the thermostat which was originally on the wall above the air intake vents to a room further from the system.

    The system is still short cycling, particularly when the day is just beginning to heat up from about the hours of 9:30 am – noon. After that point, the run times increase slightly, but the restart times remain in the 4-6 minute range. By about 2:00, the system just runs and runs and runs until it begins to cool off outside. Around 5-6 pm, it will start the short cycling all over again until later in the evening when the house starts to loose heat in the attic. I also noticed the other day that there was condensation on my ceiling vents in a couple of the rooms.

    The installer is now telling me that I need insulation in the attic and on one section of the ducts up there (he never checked it prior to installation) and that he doesn’t know what else may be causing the problem unless the thermostat needs to be recalculated. I am keeping the house set at 77-78 degrees while I am home and 80-81 when I am away, and we are currently experiencing high 90’s to low 100 degree days.

    It’s been suggested by someone else in the hvac business that the system may be too large for the square footage and that is why it’s short cycling and getting the condensation. I am absolutely beside myself as this was a huge capital layout for me and I don’t know where to start. Any advice on how to proceed or how to approach the installer would be greatly appreciated. I listen to the system short cycling and all I can think about is the damage it is doing to the compressor and what it is doing to my utility bill.

    Thanks in advance, guys! Like I said, I am beside myself with this situation (mainly with worry and considering the $ that was involved) and any help you can give me that may rectify the situation will be more than greatly appreciated.
     
    nrajeff likes this.
  2. Out West

    Out West

    Messages:
    2,919
    Likes Received:
    6,419
    Joined:
    May 24, 2001
    Location:
    Fort Worth, TX
    Frustrating! I can't help, but hoping you get it fixed. Quickly and without further expenses.
     
    nrajeff, TBO, 63Bravo and 4 others like this.

  3. JArthurD

    JArthurD Silver Member

    Messages:
    6,154
    Likes Received:
    17,794
    Joined:
    Mar 27, 2017
    Location:
    Manassas, Va
    I have a three ton unit for the downstairs area of my home. A smaller unit unit covers the upstairs and I don’t have these issues.

    The constant starting will tax the capacitor and other parts of the system so this will have to be fixed.

    Not sure what the source issue is but I don’t think the unit is too large. I’m not an expert. Just someone who has spent a lot of time running things like this down. My guess would be the thermostat, location or failure, since the unit itself is new. Replacing that is far less costly than the alternatives but it seems your warranty should still be good.

    I feel you pain on this. Been there and done that.
     
    Glolt20-91 and Foxterriermom like this.
  4. RovinOn

    RovinOn

    Messages:
    1,006
    Likes Received:
    1,255
    Joined:
    Jul 26, 2016
    Location:
    PA
    A 3 ton machine replaced a 3 ton machine which wasn’t an issue before? The system could be low on charge but I’m sure they should have already checked that.
    Depending on what type of thermostat that could be a problem.
    Cannot really say to much more of course without seeing the system.
    I just recently replaced my system here in PA. My system is only
    2 1/2 ton and made by Trane. My thermostat is computerized and when I set it for 70 degrees that what it maintains. Now it does cycle to maintain that but not on for 5 minutes and off again for 5 which I consider a short cycle.
    What does it do if you set the thermostat 72 degrees, would it stay running for a longer duration?
    I think you need to have a serious talk with your installer?
     
    NJ1911 and Foxterriermom like this.
  5. G26-Has-my-6

    G26-Has-my-6

    Messages:
    7,986
    Likes Received:
    17,898
    Joined:
    Nov 29, 2017
    Location:
    Twin Cities, MN
    3 Ton is in the ballpark for your size home if you live in south TX. frequent cycling is indicative of an oversized AC system, but if you didnt have this problem with your old 3T system, then why would the new 3T system be to blame? So it seems there are one or more small details that are causing this problem.

    other causes of short cycling:
    * Thermostat - Loose wire - Batteries weak - Close to a vent - Bad thermostat
    * Restricted Airflow (Dirty filter)
    * Low refrigerant
    * Bad control board

    You might want to contact American Standard directly, tell them the problem you are having, and that you have no confidence in the company who installed this system, and ask if they can direct you to a more reputable installer to troubleshoot the problem. However, I guess they won't know any more about the local installers than you do.

    you can also try another dealer from the website:

    https://www.americanstandardair.com/how-to-buy/find-your-dealer/
     
  6. Foxterriermom

    Foxterriermom No place like home

    Messages:
    7,079
    Likes Received:
    14,553
    Joined:
    Mar 2, 2009
    Location:
    Lone Star State
    @RovinOn yes, they have checked the charge on it twice now. The original thermostat he had one it was a Honeywell and they changed it out with an American Standard thermostat last week. I haven't tried setting it to any lower than 77 during the day, but it was also suggested to me that I might not have it set low enough for the system to work efficiently.
     
    NJ1911 and 835mag like this.
  7. snappy

    snappy

    Messages:
    2,512
    Likes Received:
    4,496
    Joined:
    Jan 10, 2008
    Location:
    North Cakalaky
    If the original installer doesn’t seem interested in helping you solve this I’d look and ask around your area and call another reputable HVAC company, have them come out and explain in detail what is going on and let them diagnose it.
     
    Foxterriermom likes this.
  8. Foxterriermom

    Foxterriermom No place like home

    Messages:
    7,079
    Likes Received:
    14,553
    Joined:
    Mar 2, 2009
    Location:
    Lone Star State
    @snappy, I have someone coming tomorrow morning. I want to make sure I understand the possible issues as thoroughly as possible can so I don't get taken for a fool.
     
    ithaca_deerslayer likes this.
  9. RenoF250

    RenoF250

    Messages:
    11,829
    Likes Received:
    8,299
    Joined:
    Feb 23, 2008
    You may very well need some insulation but that is not likely related to your problems. If 3 ton kept it cool before it should again.

    I am thinking it is either the thermostat (the AS could easily be made for them by Honeywell) or the line set for the compressor is too small. Did they install new lines? How long are they? Are they as large as the fittings on the compressor?

    I would read the manual for the thermostat and see if it has a hysteresis setting. If so turn that up. Your temp is pretty high, I would turn it down to 74.

    With variable speed blower it probably is supposed to run all the time and just adjust the blower speed to the load but it should be able to hit the setpoint.
     
    NoStress and Foxterriermom like this.
  10. Foxterriermom

    Foxterriermom No place like home

    Messages:
    7,079
    Likes Received:
    14,553
    Joined:
    Mar 2, 2009
    Location:
    Lone Star State
    They used the existing lines and did not run any news ones. I'm not sure I understand your question about the length. It's a pretty basic thermostat - not very much programming capabilities. I'll try turning the temp down when I get home and see if that makes any difference in the run performance.
     
  11. tarpleyg

    tarpleyg

    Messages:
    3,411
    Likes Received:
    517
    Joined:
    Aug 7, 2002
    Location:
    North Carolina
    When I had my first HVAC system replaced a few years back, part of the reason we went with the system we went with was because anything bigger/better would've required new lines to be run at a substantial additional cost. I don't recall the particulars but it had to do with SEER ratings and the replacement crap they use now instead of good old freon.
     
    Foxterriermom likes this.
  12. Dave514

    Dave514

    Messages:
    41,677
    Likes Received:
    42,213
    Joined:
    Jul 6, 2013
    Location:
    USSA
    I'd be looking for the oldest HVAC guy in the business, around my area, to get a second opinion.

    I'm guessing the answer is going to be some super simple issue that is just being missed. A new pair of eyes with a lot of experience may do the trick.
     
    B C, FullClip, NoStress and 2 others like this.
  13. RenoF250

    RenoF250

    Messages:
    11,829
    Likes Received:
    8,299
    Joined:
    Feb 23, 2008
    The existing freon lines between the compressor and the evaporator? That may not be a good thing. I had a guy install lines that were too small on my system. It worked okay but was bad for efficiency. Length being how far from compressor to evaporator. The farther that is the larger the lines need to be. They generally try to keep them close but sometimes they have no choice.

    Hysteresis is not a fancy setting. I think even the old mercury ones had it, it was just a screw or something. It is the difference between where it turns on and where it turns off. If that is something really small it will kick on and off. Setting it larger will prevent that but you may be able to notice the temp change as the system cycles.

    If you have a variable speed air handler it may be too smart for the thermostat.
     
  14. pgg00

    pgg00

    Messages:
    18,253
    Likes Received:
    42,222
    Joined:
    Jun 1, 2008
    Location:
    Fled the emerald triangle
    I can't see how you can stand having it that high. I keep mine at 60
     
    cougar_ml, NJ1911, mdlott and 2 others like this.
  15. Jake514

    Jake514

    Messages:
    1,491
    Likes Received:
    269
    Joined:
    Feb 3, 2007
    Location:
    Texas
    The unit size is not your problem. I live in Houston and have 472 square feet/ton. You have 490 square feet so you are ok.

    I would start with the thermostat and see if you can try a different one - maybe a loaner. They can be changed very quickly as a trial.
    Low R insulation may contribute somewhat to the problem but I do not think it is your main problem.
     
    cbetts1 and Foxterriermom like this.
  16. nerr

    nerr

    Messages:
    2,146
    Likes Received:
    3,149
    Joined:
    Jul 20, 2018
    My daughter just had her 20-year old freon ac replaced. They kept the same lines and I think the A-frame, but had to put in an adapter of some kind because the new a/c was not freon, but the new stuff. They had to make sure to purge all the old freon as well. They had some initial problems with keeping their house cool, but IIRC theirs was running all the time. I'm not sure what all they fixed, but I heard something about raising the A-frame (inside the furnace ducting, connected to the a/c line). There may have been something else done, but don't remember. It works fine now.

    If your new a/c was keeping the temperature correctly but just short cycling, not sure what was going on. New condensation on the ducts would seem to indicate either really colder air or the short cycling is not allowing the inside air to be dehumidified.

    Unless you don't like the installer, suggest you have him get the manufacturer involved. If he does not fix it pretty soon, then you call the manufacturer directly as stated in a previous post.

    Good luck and be persistent because your warranty clock has started.
     
    Foxterriermom likes this.
  17. GeoJelly

    GeoJelly

    Messages:
    121
    Likes Received:
    119
    Joined:
    Jul 22, 2001
    Location:
    NOVA
    I am old so I didn’t notice in the comments to see if someone mentioned this; that said - one easy to fix possibility is the swing value on your thermostat. I keep ours set to 1.25° this time of year, and it will run for roughly 20 to 25 minutes, and then shut down for 15 to 20 minutes, wash and repeat. If your swing value is set to .75° by default it’s going to be on and off a few times per hour. The Sensi thermostats, if you have one, are notorious for short cycling. Both Nest and ecobee say that you can adjust the swing value but that appears to be farsimonious ;) from the comments I have seen. We use a $50-ish programmable Lux thermostat from AMZ that has been absolutely bulletproof.

    Edit - Just reread your thread. Noticed that you or were using a basic Honeywell, then switched to an American Standard generic T-Stat. If your current thermostat is not programmable, then I doubt that you can change your swing value unless there is a dip switch sitting on the back of it, or something like that. I do not work for Lux and have no association with them. But, their programmable thermostats are great.
     
    Foxterriermom likes this.
  18. Foxterriermom

    Foxterriermom No place like home

    Messages:
    7,079
    Likes Received:
    14,553
    Joined:
    Mar 2, 2009
    Location:
    Lone Star State
    My office at work is so cold I currently have a heater running full blast and the warmest I can get it is 70 degrees. I would freeze at 60.

    Thermostat has already been replaced and relocated so I would be surprised if that if that is the issue. It may be set too sensitive, but the instructions that came with it are so poor I can't figure out how to change it.

    The people coming in the morning are from the longest established company in town. The ONLY reason I didn't go with them in the beginning is because I was sold on the variable speed air handler from all of the research I did and they didn't offer one. I am having severe buyer's remorse at this point...
     
    NJ1911, ithaca_deerslayer and pgg00 like this.
  19. GeorgiaGlocker

    GeorgiaGlocker Philippians 4: 6-7

    Messages:
    8,886
    Likes Received:
    10,001
    Joined:
    Jan 13, 2006
    60.....as in degrees? Good Grief!! :faint:
     
    flyover and pgg00 like this.
  20. Jake514

    Jake514

    Messages:
    1,491
    Likes Received:
    269
    Joined:
    Feb 3, 2007
    Location:
    Texas
    Variable-speed is great and you will be more comfortable with it over a fixed-speed fan. Please let us know what the culprit was once you get the short-cycling problem fixed.

    You can help yourself by continuing to document the on-off cycle times before the service person arrives.
     
    Foxterriermom likes this.