Nest Thermostat continues to heat up despite hitting the target temp

[Sleepy101]

Just installed nest 3rd gen thermostat. Everything fine the first day. I have a 2 stage carrier heat pump. This morning the temp went up to desired temp fine but around 10 am the temp was to drop to 65 ( thermostat displayed the scheduled change). The heat pump ran in 1st stage heat and only reason I noticed it was it was getting warm(74). Only way to stop this was to run equipment test on heat pump heat. I then lowered the heat pump balance to 3 hrs instead of 5 hrs, everything was fine until about 1 to 2 pm and noticed the temp going up again it was running still at 74. I did the same test to stop it. O am trying to see what s/w setting is causing the problem. I now have deleted the weekly schedule and have lowered the heat pump balance to zero hours so no preheating. I am starting to read that others are seeing similar issues. Anyone have thoughts? I may need a pro come in. One is scheduled for dec 6th. I saw Tharp I may get a credit? Is this true?

[Sleepy101]

Update, started doing it again. Suppose to have a temp of 65 current temp in house 71. Heat pump started up in low stage furnace fan barely blowing but the air coming through the vent was slightly warm. I just pulled the nest and put my old aprilaire thermostat back on. I need a comfortable night sleep.

[EdwardT]

Hi folks,

@CoolingWizard, thanks for the help!

@Sleepy101, how's it going with your Nest Thermostat? Still need our help?

Thanks,

Edward

[Sleepy101]

I will attempt the recommended settings once I get home tomorrow. Celebrating thanksgiving with family in a different city. I appreciate the assistance and will reply with results by Saturday this week.

[EdwardT]

Hi Sleepy101,

Thanks for the update. Let us know the results once you've tried the settings. Keep us posted.

Thanks,

Edward

[Sleepy101]

I connected the nest up and tried the settings suggested. Still would run a very light air flow through the vent and temp was 73 and slowly climbing. I have our hvac people coming Tuesday this coming week. I connected old thermostat back up. I will let you know what my hvac person says….

[CoolingWizard]

Some people make the mistake of setting the ECO and Safety temperatures incorrectly. This will cause the system to operate outside normal operating intentions. Make sure for now you turn off Home/Away assist, turn off Auto-Schedule, turn off Early-On, turn off Cool-to-Dry, and Sunblock Off. Then, choose a mode, Heating, or Cooling, set the desired temperature and see if it behaves properly.

Ken, The AC Cooling Wizard

[Sleepy101]

Thank you for the suggestions . I set it this way and still happening. Heat pump still continues to run. I want to make sure there isn’t something on my carrier heat pump or furnace.

[CoolingWizard]

You need to check the system configuration you have. What is set as the primary heat source, and what is set as the auxiliary heat? Since you have a heat pump, your primary heat will be the heat pump and at a specified outdoor temperature, the heat pump can be turned off and the gas furnace becomes the heating source. Now, do us a favor, post a picture of your original thermostat backplate with the wires attached. Thank you ,

Ken, The AC Cooling Wizard

[Sleepy101]

Ken, I wish I could just send you an email…..

[Sleepy101]

https://drive.google.com/file/d/1EeFMUpzReJaLmWuLLzug2e1W_B3To6K8/view?usp=drivesdk

[Sleepy101]

I tried to copy and paste the pic but it said I did not have permissions to upload images….I hope the link works….

[JacideLange]

Hi Ken

I wonder if you can help me. My Nest Sense doesn't have the Early On function under Settings, and my boiler seems to be turning on and off, as and when it desires, despite my having set a schedule. At times I wake up in the middle of the night and it is on but it shouldn't be. It also has a 'preheat' setting that I can't get rid of. At times it turns itself on 2 or more hours before it should. I am trying to save energy costs and I am at the end of my tether. How do I correct this to have the thermostat simply work as a thermostat?

Thank you

[CoolingWizard]

Hellom JacideLange,

in your nest app, when you open the Nest app, you’ll see your home and your thermostat tap the thermostat. Once that opens in the upper right tap the settings gear. Scroll down and you’ll see where you can turn off the the early preheat. When I began the troubleshooting process of things, like this, I go into the Nest app, and I turn off Home/Away, Auto-Schedule, Cool to Dry, Sunblock, and Airwave.

Ken, The AC Cooling Wizard

[Jhonleanmel]

Hey folks,

We appreciate your help here, @CoolingWizard.
@JacideLange, I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any concerns or questions from here, as I would be happy to take a closer look and assist you further.

Thanks,
Mel

[Sleepy101]

MY UPDATE…..

Sorry, been busy with other things. I paid for my HVAC people to come to my house to see what I am experiencing and see if they could get it working correctly. They looked at all my settings and corrected one setting where I had not selected dual fuel and he said because I have a heat pump and also heat strips in the furnace( used for real cold days I live in Central Oregon) it needed to be dual fuel. Ran tests on all phases and everything worked fine. 40 minutes after they left heat came on( thermostat set for 68 but temp showed 70) it just kept running( heat pump stage1). Turned setting for heat off it still ran. Only way to stop it was to turn power off at the circuit breaker. HVAC told me that after researching and talking with others I needed to return this thermostat for a new one. I called google support and the old one is on its way to Texas and they will send me a new one. I will try and set this up when it gets here…

I wired it correctly, only one setting was not correct but they didn’t think it was causing the issue. Also I have a 2stage carrier heat pump and multiple speed fan in the furnace. Everything there they tested showed up working fine. It gets maint checks every 6 months just to make sure it works efficiently…

[Jhonleanmel]

Hi Sleepy101,

Thanks for the update. Keep us posted for when you are able to setup your new Nest Thermostat.

Best,

Mel

[Jhonleanmel]

Hey Sleepy101,

Checking back in should you still have some questions here. Let us know by replying to this thread.

Best,
Mel

[Sleepy101]

I will do that, waiting on google support to send us a new nest…

[Jhonleanmel]

Hi Sleepy101,

Thanks for letting us know. Take your time, I'll be waiting for your update.

Best,
Mel

[Jhonleanmel]

Hey there Sleepy101,

Checking back in should you still have some questions here. Let us know by replying to this thread. 

Best, 
Mel

[Sleepy101]

I sent an image of the original wiring of old thermostat directly to Ken the ac cooling wizard. In short I have 7 wires used. Blue wire goes to c; yellow wire goes to Y1; black wire goes to Y2; orange wire goes to O; green wire goes to G; red wire goes to Rc and it is jumped to Rh; white wire goes to W.

I hope this helps. I put all wires to appropriate colors on the nest intries red wire to Rc. Received the problem then the next time I tried Rh and still received the problem.

[CoolingWizard]

When it comes to the nest thermostat, let’s do a check of the wires it recognizes, I assume the nest is still installed correct? We need to wake up the nest, rotate your ring, and select settings, rotate to ring to nest, pro and select. After that you will see the back plate and the wires that the nest is currently recognizing as active and installed. With each will be a little wedge it’ll either be green or yellow. If it’s green nest is happy with it and it’s working the way they expect. If it’s yellow Ness doesn’t recognize it. We will need to rotate the ring to a yellow one press select, and define its function. Your current wire functions are:

Red Wire: RC is Power IN

Yellow Wire: Y1 is Compressor Stage 1

Black Wire: Y2 is Compressor Stage 2

Green Wire: G is Blower Fan

Orange Wire: O is Heat Pump Reversing Valve; changes system mode Heat or Cool

White Wire: W is alternate heat or auxiliary heat.

Now I need to talk a little bit about a heat pumps. What you need to understand is all heat pumps manufactured have a Reversing Valve to change the mode from heating to cooling or from cooling to heating. Now by default all outdoor units, manufactured as heat pumps will default to heating or to Cooling. This ensures if the reversing valve coil fails, it will still provide its basic unenergized mode. In the desert southwest, we install default cooling systems, and the Northeast they tend to install systems that default to heating.
When you followed the steps to install your Nest Learning Thermostat, when perform the Heating and Cooling tests, did they operate properly?

Ken, The AC Cooling Wizard

[Sleepy101]

First, I want to thank everyone for willing to help figure out how to get a nest thermostat to work. I received the replacement 3rd gen Nest and today I installed it. I have very limited settings per Ken. So for 3 hours now everything has been okay. I will keep it on the basic settings with no learning turned on. No scheduling, or eco settings. I want to keep this going for a few days to see how things go. So far so good!!!

 Don Stupfel

[CoolingWizard]

Don,

That is outstanding to hear Don.  The only real purpose for the automatic schedule feature is for somebody who doesn’t quite understand how to set up a manual schedule in either the heating schedule or the cooling schedule. This works best however, when somebody has a very rigid schedule of life. And that means that at the time you get up, you make it a temperature change, when you leave the house, you make a temperature change, when you get home at the end of the evening, and make a temperature change, and when you go to bed, you make a temperature change. When you do something like that, then study automatic schedule can be efficient and useful. Now , here is what I do.

First, I set the mode to Heating.  Then I create a heating schedule. I set the morning time and temperature for Monday, then copy to the rest of the week. The repeat for the late morning and evening and finally bedtime. I repeated this process by building a cooling schedule as well. When you go to create a schedule, you can only create the schedule for the mode. The system is currently in. So you have to switch it to cooling mode set the temperature really high, build your schedule. Once the schedules are built, then you can decide what you want to do. You can use her schedule or choose not to use the schedule. You can override a schedule by changing the temperature however the nest always seems to do a reset every hour going back to the active schedule. Overtime you will have the heating and cooling schedule just the way you like it. Now come to the power-play. The nets can be put in the mode of heat/cool instead of one of the other. When it does that it applies both the heating and cooling schedule and it will maintain a very specific temperature despite what’s going on outside. It will either heat your home or cool your home to maintain that temperature and you don’t have to change modes at all. And, lastly. I use the ECO schedule when I’m going to be gone from the home for extended period of time and when I say extended period of time I mean for weeks or days. again, I hope this helps you.

Ken, The AC Cooling Wizard

[EdwardT]

Hi folks,

@CoolingWizard, we always appreciate the help!

@Sleepy101, I'm glad to hear that everything is working fine now. Please observe it for now and let us know if anything comes up.

Thanks,

Edward

[Sleepy101]

Hi there, yes so far everything is fine.  I do have a question.  

Single fuel vs dual fuel setting. I have an electric system where I have a heat pump( 2 stages) and aux heating( metal strips) in furnace. I see it a single fuel system but the hvac guy said it was dual system. I do not agree with him and I did the single fuel system. There is a setting that asks you what temp do you want compressor not to be used. He had set the old nest thermostat to 30 degrees. Then confirmed that the aux heat would be used if colder than 30 degrees.

I had a dual fuel system before( natural gas furnace and electric heat pump/AC). So I know what dual fuel is. Everything works set up as single fuel. The question is the temp to force aux heating. Does 30 degrees seem like a good number?

thanks again!

Sleepy101( Don Stupfel)

[EdwardT]

Hi folks,

@CoolingWizard, we always appreciate the help!

@Sleepy101, I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

Thanks,

Edward

[CoolingWizard]

Hello Sleepy101,

The answer to your question about. When do you cut over from the heat pump to some other form is immaterial in your particular case. Both your heating systems are electric-based. The heat pump will provide heating all the way down to about -5°F. The efficiency is measured in something called COP and basically the electric heat strips have a COP value of 1.0 where the heat pump is about 2.45 at 30°F.  In your particular case, your heat strips are basically the auxiliary heating so if the heat pump ever ices up outside, it has to defrost and the auxiliary heating is needed. 

The term dual fuel is a little bit of a misnomer when it comes to the HVAC heating system. What’s really being described as the fact that you have two different sources of heat. Your first is heat pump it’s electric, and your second is resistive heat strips, which are also electric. The point is though there are dual heat systems. now you can treat the electric strips as emergency heat and then you would have basically a single fuel source be in heat pump for heat. If the heat pump ever fails, you got electric strips to keep making heat so you don’t freeze to death until the repair guy shows up.  I hope this helps you to understand. 

Ken, The AC Cooling Wizard

[Sleepy101]

Thanks for all the help from you all. I think we are good. If I changed from single fuel source to dual fuel source I am not sure I would know what the strings would be. The settings for dual fuel forced me to call for help from professional services. So I selected single source instead…we are happy how things are working with the current settings. I may change the temp to force aux heating to a lower temp at some time in the future….

[Sleepy101]

String = Settings

[EdwardT]

Hi Sleepy101,

Thanks for the update. I'm glad to hear that you were able to figure it out. Please observe it for now and let us know if you have questions.

Thanks,

Edward

[Sleepy101]

Thanks Edward!! I will continue to observe. So far everything is fine…

Don

[EdwardT]

Hi Sleepy101,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[EdwardT]

Hi Sleepy101,

I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

Thanks,

Edward

[EdwardT]

Hi Sleepy101,

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Thanks,

Edward

[Sleepy101]

Thanks for checking in Edward. Even though I could change the setting to dual fuel the nest thermostat is working fine with the setting set for single fuel and so the heat pump does the heating until the temp outside goes below 30. That is when the Aux heating kicks in. It has been working fine since we got this one from google to replace the first one….go ahead and lock this one and I want to thank everyone who assured through this community!! 

sleepy101.   

don s

[EdwardT]

Hi Sleepy101,

Thanks for the update. I'm glad to hear that the replacement that you received is working fine. I will be locking this thread now. Please feel free to create a new thread should you have some more questions or concerns in the near future and we'll be more than glad to help.

Thanks,

Edward