Need some serious hvac advice!

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

  1. Micad

    Micad

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    A couple of years ago we had an American Standard system installed to replace the existing unit. It had the variable speed fan also, much like your system. One thing to check though, is whether the compressor is a 2 stage compressor. The system we put in was a 2 stage compressor and had to have a compatible thermostat. Installer had to go get one and said the regular one would not work correctly.
    Good luck to you and relax a little. They will get it figured out and you paid them a lot of money for a system that works correctly, don't settle for less.
     
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  2. Foxterriermom

    Foxterriermom No place like home

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    @Micad , the paperwork says it's a single speed compressor.
     
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  3. manfred the wonder d

    manfred the wonder d

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    I did hvac for 20 years. I don't believe I ever found a bad thermostat to be the problem.
    You want the unit sized to run constantly on the hotest day. Lowers the humidity and you feel cooler cheaper.
    I think they just dont have the experience. An amp probe can easily tell them how hard the compressor is working.
    I love the variable speed units by the way. They don't wake you when they come on. Good luck.
    Probably something simple.
     
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  4. faawrenchbndr

    faawrenchbndr CLM

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    Your new system is oversized due to the greater efficiency vs your old unit
     
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  5. Foxterriermom

    Foxterriermom No place like home

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    If this is the case, do I insist with the installer that he replace it with a 2.5 ton at his expense? I would I prove that is the problem?

    ETA - the other two quotes I received were for 3 ton systems as well. This one is 16 seer, as was another one, and the third was for a 15 seer.
     
  6. Resqu2

    Resqu2

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    Tagging in to see what happens tomorrow, best of luck! I’m guessing there is a bad part/board somewhere on the outside unit. I take care of a bunch of units at work and American Standard are my best units.
     
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  7. cbetts1

    cbetts1

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    I also think new unit is more efficient so temp is brought down but doesn't run enough to reduce humidity.

    This is a problem with new homes that use foam insulation and high efficient units.

    HVAC systems are supposed to be engineered based on requirements (SF, lay out etc)
    You don't just throw in same tonnage because that's what was there.
    Your installer should be able to provide you with the paperwork that shows why they went with that sized unit. Same with ducts.

    If installer says problem is lack of insulation, you may be able to get a free audit from electric company. Some get high tech with flir etc.

    If that doesn't help call manufacturer to get qualified tech. If you can get someone to tell you something is not correct, it will give you guidance on what to pursue.

    Make sure you filled all warranty info out.
     
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  8. Foxterriermom

    Foxterriermom No place like home

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    I'm glad to hear that about American Standard. I tried to do my due diligence when researching what brand to go with. I narrowed it down to American Standard, Trane, and Carrier.

    I filled out the warranty info online the day after it was installed. The installer never even mentioned that I needed to take care of that.
     
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  9. mdlott

    mdlott

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    This too shall pass. Relax, breathe and execute your plan.
     
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  10. cbetts1

    cbetts1

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    One more thing.
    If you set a appointment, try to set it for part of the day where temps will cause the unit to cycle so they can observe it doing the things you talked about.
     
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  11. Micad

    Micad

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    Well, that eliminates that.
     
  12. inthefrey

    inthefrey Moved on...

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    Does the control board on the new system have any type of "logging"? If it is "short cycling", there's only a few issues at play here. The system is satisfied or high-pressure/low-pressure sensor is yelling at the control board to stop. Thermostat should have some type of "window". If that differential is set too narrow, it WILL short cycle.

    I did't read the entire thread but, It sounds like you may need to disable the automatic feature of your air handler. I assume it is using a delta between the air temp and the evap temp or pressure to decide when to stop the compressor. Not enough flow can play havoc with newly installed systems. And, computer-controlled systems ARE THE DEVIL!
     
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  13. winchester62

    winchester62

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    This is not a valid concern. Not the chest pain part (hopefully just a little heartburn), but the "not having a grasp" of the mechanics or being the "problem customer." I don't post here often but I've been here a long time. For a woman *OR* a man, you are being very analytical regarding understanding the system and helping your technician to diagnose your problem. Rest easy. As much as this is stressing you out, it WILL get fixed in short order and you have helped yourself tremendously in resolving the issue. Don't sell yourself short. :)
     
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  14. Foxterriermom

    Foxterriermom No place like home

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    Yes, I think the tolerance between the set temperature and the room temperature may need to be adjusted, but I can't figure out how to do it from the user guide. Also, the inside system located is in the center of the house in a corner and although there were already two air intake vents, they installed an additional one so it wouldn't be air starved.

    Thank you for the vote of confidence and the encouragement.
     
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  15. dac1204

    dac1204

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    A Tom is about 600 sqft so a three ton is over sized a 2 ton would have been better.


    you are getting the condensation because of the short cycling. The blower motor is pushing to much air across the coil allowing water vapor to not be removed.

    A psc motor will run at one speed (whatever speed tap it’s set on) while an ecm or variable speed will ramp up or down the speed to compensate.

    An ecm motor running at full speed is why not enough moisture is being removed from the coil.

    that’s not the underlying problem.
    My guess it’s a oversized unit



    I could see an old t stat giving a problem but most modern ones would be ok.

    If you have a thermometer stick it in the vent while it’s running and see what the temp is.

    then find your return and stick it in that vent while unit is on and see what the temp is. You should have somewhere between a 15-20 temp difference. So supply is 50 then the return should be around 65-70 degrees.

    I know you said another HVAC company is coming but just a little FYI.

    the old line set is most likely not the problem. 410-A can use existing line sets up to certain lengths which usually stop at around 70 feet before going to the next size.

    I re use them all the time I just flush them and pull good vacuums before letting the 410-A into the line set.

    Did they do a load calculation or just quote you basedon what was there?

    you have to remember that older systems were not as efficient as newer systems are. Just because a three ton was there doesn’t mean it belonged from the beginning.
    The new company should have done the calculations.
     
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  16. dac1204

    dac1204

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    almost all new t stats won’t let you set the anticipator anymore unless it’s a digital stat. I use basic white Rodgers if the customer doesn’t specify what they want. Simple up and down buttons with slides for AC and heat.
    If you can get a Honeywell pro6000 like the one pictured above. Has WiFi and is user friendly once programmed.


    You can set the points on it
     
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  17. Foxterriermom

    Foxterriermom No place like home

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    Met with the representative from a competitor (from the Carrier dealer) this morning, and he believes my system is over-sized for the house. When he figured their quote for me last month, he figured a 3 ton system keeping it at an average temp of 68. When I told him I keep it between 76-78, he said a 2.5 ton system would be all I needed. He also couldn't understand why they moved the thermostat off the air intake wall.

    I think I need to call the manufacturer and discuss this with them before I call the installer again. If they confirm this is the case, I have no idea how I go about telling this guy he put in the wrong system and need to replace it. He's gotten paid for the job so I feel like I am at his mercy.
     
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  18. syntaxerrorsix

    syntaxerrorsix Anti-Federalist CLM

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    My system does a pretty good job of keeping the house at 72F. The system nor my wallet could keep it at 60F. I'm filing this under "it must be nice" :supergrin:
     
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  19. manfred the wonder d

    manfred the wonder d

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    Seems to me the unit size is about right. What if you sold the house and people that liked the temp 72 -73. You would need another unit.
     
  20. Foxterriermom

    Foxterriermom No place like home

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    @syntaxerrorsix I would freeze at 60 degree and even 72 would be colder than I would want. What size unit do you have? Does it run continuously? The guy this morning told me I shouldn't be concerned if the system runs all day long.