Early on starting consistently late

[bkspero]

My 3rd gen Nest thermostat is not turning on early enough to heat the house to the morning setpoint in the prescribed time.  Otherwise the thermostat is working as it should.

As for settings...Early-On is on and the maximum duration is set to 5 hours.  The schedule calls for an overnight setpoint of 64 deg F and an increase to 70 deg F at 7:30 AM.  Auto-Schedule, and Home/Away Assist are off, as are Cool to Dry, and Sun Block.  In Settings, the Early On entry says On-Ready right now (it is mid-day).

Like clockwork Preheating starts at 6:00 AM every day (exactly 1 1/2 hrs prior to the setpoint change time).  On warmer nights the morning setpoint can be reached in time with stage 1 heat.  Most nights, however, there is no chance that the setpoint will be reached by 7:30 and the furnace switches to stage 2 heat at about 6:60-7:00 AM but the temperature is still 66-67 F at 7:30 (when it should be at 70F).  It has operated this way for this way for a couple of months.

What can I do to get it to preheat correctly? 

[virnab]

Hi bkspero,

Thanks for reaching out to our community.

I’m sorry to hear that your Nest Learning Thermostat (3rd gen) is not turning on early enough to heat the house to the morning setpoint in the prescribed time. Thank you for letting us know that the thermostat is working as it should and providing details on the way you’ve settled the Early-On schedule, so I can better understand the inconvenience that you are experiencing. No worries, help is here.

Before I start further troubleshooting, let me ask you a few questions:

• Is Autoschedule activated?
• Have you ever worked early on before?
• Could you please double-check if there is another schedule that interferes with this early schedule?

Thanks for your kind attention; I will be looking forward to your answer.

Best regards,

Virna

[bkspero]

Sorry that I am so late responding.  Autoschedule is not and has never been activated.

Early on worked last year. To the point that I reduced the maximum Early On time to 3 hours from the default 5 hours last year.  This year I left the Early On time at the default 5 hours when I reset the thermostat to it's factory defaults when we had our HVAC system replaced in August. It is still at 5 hours.

There is only one schedule and it is the same for every day.  Set to 70F at 7:30AM, set to 64F at 10:30 PM.

BTW, since my note I did a restart of the thermostat (not a reset, just a restart), and turned Early On off and back on. This did not correct the late start for preheat either yesterday or today.

Thanks for responding, Barry

[virnab]

Hi bkspero,

Thank you for your kind answer, providing me with more important information about your Nest Learning Thermostat (3rd gen) that allows me to better assist you. 

Considering the troubleshooting steps you have tried without success, I recommend you change Early-On settings using the Nest app. In some homes, Early-On might use more energy because it runs your system longer. You can either limit the preheating time or turn Early-On off to help save energy.

Here are the instructions to change the Early-On setting with the Nest app:

1. Open the Nest app.
2. Tap your Nest Learning Thermostat (3rd gen).
3. Select “Settings.”
4. Tap “Early-On.”
5. Choose from the following options:
• To limit preheating in the middle of the night and early morning, select Max Duration. This setting can be useful if your system is noisy, and you don’t want it to wake you up too early.
• To enable or disable Early-On, tap the switch.

Please let me know how it goes.

Best regards,

Virna

[bkspero]

Virnab, thanks for the quick reply. Unfortunately, I don't see how your recommendations will achieve my objective of having the house reach its 70F setpoint by 7:30 AM every day as the documentation claims it will do. I want it to start as early as 2:30 AM if that is what is needed to reach the 70F setpoint by 7:30.  That is why I have already set the Max Duration value to 5 hours.

Also, all the changes that I have made (except for the thermostat restart) have been made using the Nest App.

What else can be done to get the thermostat to function as its documentation claims?

[virnab]

Hi bkspero,

Thanks for your prompt response.

Please excuse me if you perceive my recommendation isn’t related to achieving your objective. The procedure that you are asked to do is because it is necessary to review from the smallest detail to the most complex to determine where the inconvenience is.

Please let me know how it goes after performing the previous recommendation. If the inconvenience persists, I would appreciate it if you could provide me with the following information:

1. What kind of HVAC system do you have?" (Heat pump, conventional system, etc.)
2. What country are you located in?
3. Have you experienced any power outages within the last two months?

Thanks for your kind attention; I will be looking forward to your response.

Best regards,

Virna

[bkspero]

I have done the steps you suggested previously (using the App) and there was no change other than the system did not attempt to preheat when Early-On was turned off.

The HVAC system consists of a 2 stage natural gas fired forced hot air furnace for heat and a 2 stage air conditioner for cooling.

I am located in the USA on the east coast (state of New Jersey).

We have not had any power outages in the last 2 months. The only time that power was out to the furnace area was last August when the new HVAC system was installed.

Thank you for your consideration.  Barry

[virnab]

Hi bkspero,

Thanks for keeping me up to date about your case. I really appreciate your collaboration following the instructions and for your timely response providing me with the comprehensive information, because it allows me to better assist you.

Based on the information you provided me, I recommend the following troubleshooting steps:

Remove your Nest Learning Thermostat 3rd gen from your account:

1. Sign in to the Nest app.
2. If you have another home, on the app home screen, tap “Menu.” Then select the home that has the product that you'd like to remove.
3. On the app home screen, tap “Settings.”
4. Tap your “Nest Learning Thermostat 3rd gen.”
5. Scroll down and select ‘Remove Nest Learning Thermostat 3rd gen.”
6. You'll then be asked to confirm your choice.

Factory reset your Nest Learning Thermostat (3rd gen). This option will remove all your personal settings and restore your thermostat to factory default settings. 

1. Go to Settings
2. Select the option “Reset.”
3. Select “All settings.” 

After you reset your thermostat, you'll need to set it up and add it to your home in the app again just like you did when you first installed it. Please check the following articles to follow them:

How to set up your thermostat

Add your Nest thermostat to the Nest app

Your thermostat will need time to learn about you and your home before it creates your schedule and activates its energy-saving features. For more information, you can go to this article: How Nest thermostats learn.

Please let me know how it goes.

Best regards,

Virna

[bkspero]

Thank-you.  I will give it a try.  Barry

[SayreM]

I’m having a similar issue. In my case I noticed this problem about two weeks ago. I have tried a similar set of troubleshooting steps as bkspero. I also tried shortening the early on maximum time. When set to two hours, at least on one day, the system worked. Like bkspero, a two hour window required stage 2 heat to hit the target and required about three hours to do so.

I will give the system reset a try but I think there is a bug in the software as the root cause. 

[bkspero]

I agree with you. Recently it's been less clear that the system is continuing to start late, as it's been cold enough overnight that the heat runs periodically just to maintain the overnight setpoint.  But on some days the timing is right and it's clear that preheating started only about 1.5 hours from the target time.  So making all the suggested changes plus resetting the maximum preheat time to 4 hrs from 5 hrs did not correct the situation.  Just looks like the software can't perform as advertised.

[virnab]

Hi Bkspero,

I’m sorry to hear that the troubleshooting provided didn’t help to turn on the “Early-On” schedule  to heat your house to the morning set point in the prescribed time. We continue working for you, looking for the solution.

My team would like to know more about this behavior. When you get a chance, please fill out this form. Remember to include the link to this post. Let me know when you’re finished. From there, we'll contact you via email.

Let me know when you're finished. Your confirmation is crucial to ensuring that I can follow up on your case effectively.

Best regards,

Virna

[SayreM]

I reset the thermostat to factory settings and then added it back to my account. Interestingly, the Nest app retained all of the historical data. If the software glitch has something to do with corrupted data on how fast the home heats up, then this reset appears unlikely to resolve the issue. We shall see what happens tomorrow morning.

[adamtalbot]

How did you get on with the full factory reset? This is the next step I'm considering trying. 

[virnab]

Hi SayreM,

Thanks for reaching out to our community.

I'm sorry to hear you're experiencing a similar inconvenience to what bkspero reported with their thermostat, which is not turning on the "Early-On" schedule to heat the house to the morning set point at the specified time. I appreciate you letting us know you already tried the troubleshooting steps previously provided in this thread but didn’t help you to find the solution. It is my pleasure to continue trying more alternative solutions.

To better assist you, I would appreciate it if you answered the following questions:

1. Could you please confirm which Nest Learning thermostat model you have? For your reference, you can check out this article on How to tell which Nest Thermostat you have.
2. What kind of HVAC system do you have?" (Heat pump, conventional system, etc.).
3. What color does the thermostat screen become when you want to cool?
4. What color does the thermostat screen become when you want to heat?
5. What country are you located in?
6. Have you experienced any power outages within the last month?
7. Is Autoschedule activated?
8. Could you please double-check if there is another schedule that interferes with this early schedule?
9. When was the last maintenance check for your HVAC system?

Besides this information, please send me a video showing what happens while you are performing the factory reset to your thermostat.

Thanks for your kind attention, I will be looking forward to your response.

Best regards,

Virna

[SayreM]

Virna,

1. Could you please confirm which Nest Learning thermostat model you have? 
   1. Model: Display 2.5
2. What kind of HVAC system do you have?" (Heat pump, conventional system, etc.).
   1. Heat is conventional natural gas with a 95% efficient, 2 stage furnace plus air conditioner
3. What color does the thermostat screen become when you want to cool?
   1. Blue
4. What color does the thermostat screen become when you want to heat?
   1. Orange
5. What country are you located in?
   1. United States
6. Have you experienced any power outages within the last month?
   1. No
7. Is Autoschedule activated?
   1. No
8. Could you please double-check if there is another schedule that interferes with this early schedule?
   1. The schedule is simple. Set to 67 F at 7 AM and 60 F at 9 PM.
9. When was the last maintenance check for your HVAC system?
   1. About 2 years ago.

M

[SayreM]

I did not record a video while doing the factory reset. Sorry but I am not willing to do a second factory reset again at this time.

[adamtalbot]

Strangely, my Nest thermostat seems to be having the same problem as the OP and had started exhibiting this behaviour at a similar time.

I've had my Nest thermostat for a few years and have never had a problem. 

In the last couple of weeks, "Time-to-temp" is clearly not working. 

I aslkfor a temperature of 20 degrees celcius to be reached by 8:15am. For the last couple of weeks, I'm lucky if I get to 17.5 degrees celsius - the thermostat is simply not starting early enough. 

Has there been a recent update which has affected "Time-to-temp"? 

[virnab]

Hi adamtalbot,

Thanks for reaching out to our community.

I’m sorry to hear that you’re experiencing a similar inconvenience as bkspero is reporting in this thread, but in your case during the last couple of weeks the “Time-to-temp” feature isn’t working. Thanks for sharing with us additional information to have a better understanding about the inconvenience and help you to find the solution. No worries, help is here. 

Before I start providing assistance, I have a few questions for you:

1. Could you please confirm which Nest Learning thermostat model you have? For your reference, you can check out this article on How to tell which Nest Thermostat you have.
2. What kind of HVAC system do you have?" (Heat pump, conventional system, etc.).
3. What color does the thermostat screen become when you want to cool?
4. What color does the thermostat screen become when you want to heat?
5. What country are you located in?
6. Have you experienced any power outages within the last month?
7. Is Autoschedule activated?
8. Could you please double-check if there is another schedule that interferes with this early schedule?
9. When was the last maintenance check for your HVAC system?

In your case, please confirm that the "Early-On" schedule is activated in addition to starting the "Time-to-temp." Here are the instructions to change the Early-On setting with the Nest app:

1. Open the Nest app.
2. Tap your Nest Learning Thermostat (3rd gen).
3. Select “Settings.”
4. Tap “Early-On.”
5. Choose from the following options:
• To limit preheating in the middle of the night and early morning, select Max Duration. This setting can be useful if your system is noisy, and you don’t want it to wake you up too early.
• To enable Early-On, tap the switch to “on.”.

Please let me know how it goes.

Best regards,

Virna

[SayreM]

The full factory reset did not resolve the issue, although it might be marginally improved. The algorithm seems to decline to start early on before a little less than two hours prior to the target even though the limit set for early on is 5 hours. 

What is different since the factory reset is that the Nest is realizing that it cannot hit the target in the remaining time so it is calling for Stage 2 natural gas heat much earlier in the morning heat up process.

[SayreM]

After two more weeks, the Nest called for the furnace to turn on early, about 5 minutes prior to 2 hours, despite the setting allowing the algorithm to use up to 5 hours. We had almost two weeks of overnight low temperatures between 22 and 27 F allowing observation of the algorithm without the noise of more temperature variation. This is clearly different compared to last winter. It would be nice for Google to fix this bug.