Temperature overshoot

[CD10]

Even though I have true radiant turned on and early-on set to 5 hours  (concrete in-slab heating) the Nest never has the room temperature up to the set temperature in the morning and then keeps the boiler running until the room temperature reaches the set temperature which means the temp keeps rising until it's 3 degrees too high about an hour later.  Any suggestions?

[CoolingWizard]

The Nest Learning Thermostat learns over time how long it takes to heat the space. When you set the Early On the learning thermostat has to “Learn” and that takes time. The longer it is operating the better it gets.  How long has your Nest Learning Thermostat been operational. Also, it has 5 temperature sensors inside and typically is pretty accurate.  Now, if you are heating the floor, it takes time to radiate that heat into the air as well. 

Or, are you saying you set 78 degrees the thermostat is reporting 81 degrees before it turns off the radiant heating system?

[CD10]

Hi CoolingWizard.  The Nest has been installed for over 2 months now.  Even though early start is turned on, it is never up to the set temperature by 8 am (the time I’ve set for that temp).  And then it doesn’t stop calling for heat until it senses the room temp is 20 (68) which is what it is supposed to heat to.  Because of that, and since it takes awhile for the heat to dissipate to the air from the concrete floor, the room temp gets up to 23 (73.4) about an hour after it reaches 20 and the boiler is no longer working.  I thought the Nest would learn to anticipate when to start calling for heat so the room would be up to the temp I have set for 8 am, and also anticipate how much rise would occur after it quits calling for heat and shut down so as not to overshoot the target temp.  But neither the time to temp or anticipation for reaching target seem to work. I have left the old thermostat beside the Nest so I can see the temp the Nest is registering is within .1 degree C of the old one.

[CoolingWizard]

The problem that thermostats have always had is the proper value for the anticipator. In the old style thermostats the installer could set the anticipator to it would shut the system off before the desire set point is reached.  I am not aware of any way to set an anticipator type value in a nest thermostat.   What this anticipator does is cause the thermostat to shut off the system a couple degrees before the set point is reached. It was set by a bit of trial and error at times.  

Perhaps you try a work around.  For example, set a lower set point, say 19 or 18 for 1-hour sooner.  Then see how the temperature glide goes.  What some have done is get and use a Google Nest Temperature sensor.  They mount it closer to the floor than the Nest Thermostat, in the case of in-floor radiant heat, place it about a meter or slightly less above the hard floor.  It gets linked to a Nest 3rd generation or a Nest-E thermostat. The remote temperature sensor does not work with older nest thermostats.  

[CD10]

I might try setting it for 19 an hour earlier and see how that works.  Frustrating though since most "smart" thermostats I have had do a better job than the Nest (smaller temperature swings).  I thought I was buying new technology that would improve on my old smart thermostat.  Thanks for the suggestion.

[MaicoRider]

I agree with the issues CD10 has brought forth on this topic. I would think the Nest developers could add some variables to the settings menu to lessen the swing in room temperature without 'work arounds'.

[Jhonleanmel]

Hey MaicoRider,

We're always looking for ways to improve and we'll take it as feedback.

I also suggest that you send feedback by following this link. Let me know if you have other questions or concerns, otherwise I’ll be locking this thread after 24 hours.

Best,

Mel

[CD10]

Hi Mel.  I started this thread and still have not had any suggestions that work to solve the problem.  I tried setting a target temp 1 degree lower than the final desired temp an hour before I wanted the final temp hoping that might work, but it doesn't - the thermostat overshoots every day. Heating is boiler (hot water) in the concrete slab floor.  If I don't allow any setback the thermostat keeps the room temp to within +/- .5 degrees C of the set temperature.  Do you have an answer, or is it a problem with the thermostat that cannot be solved?

Cheers.

Charles

[Martijn___]

exact the same situation here.

Installed nest V3 for 2 months with floor heating.

45-60 minutes to late before SP is reached.

Every time 1C /2F overshoot.

No correction from Nest at all.

[Joeyb1156]

I posted a separate thread a few days ago regarding the same issue. I installed a 3rd GEN learning thermostat a few weeks ago, and it keeps overshooting my target temperature by 2° to 3° every time there’s a call for heat. The thermostat is running the boiler way past the time that it has hit the target temperature and then stops. My system is a boiler with Cast iron radiators, I have selected the true radiant feature. The true radiant feature does not appear to be working correctly, when viewed in the app it displays on and ready, but it never indicates that it’s learning like the auto schedule feature. I bought a second nest learning thermostat to install and it behaved the exact same way. I reset the thermostats numerous times, and finally noticed that the sunblock feature went from on/ready status to on/learning. But yet I still cannot get the true radiant feature to go into learning mode.I have called customer support numerous times, and they have been of no help. This is definitely a serious software bug or something with the thermostat.

 

 

[CD10]

It is pretty frustrating.  I was an early adopter, using “smart” thermostats since the mid-1980s, so have had several different makes and models.  All in homes that use a boiler to heat water to provide heat.  The Nest thermostat has been the biggest disappointment, especially since they are far from the cheapest learning thermostat out there.  I have given up on using the setback or learning feature and have the thermostat set to simply maintain the same temperature 24/7.  I do not recommend Nest thermostats for radiant heating. Buy a cheaper make/model and you will likely see better performance.

[Markjosephp]

Hello folks,

I'm sorry for the late response. I know it has been a while, but I wanted to ensure that everything was covered here.

We hear you all, and I understand your thoughts about this. We're always looking for ways to improve, and we appreciate your feedback. So, please, if you have a learning thermostat (the Nest Learning Thermostat 3rd generation and the Nest Thermostat E), make sure to disable the auto-schedule to avoid temperature changes automatically.

If there’s anything else I can help you with, please let me know. Otherwise, this thread will be closed in 24 hours.

Regards,

Mark

[Joeyb1156]

Mark, out of curiosity, why are you closing all these threads and not following up to make sure that members are contacted by your upper team? You did the exact same thing to me early last week, and I heard from no one as of yet. Doesn’t seem like Google wants to fix these issues. The true radiant feature has been an ongoing issue and it’s a widespread problem. If you were truly trying to help someone, you would leave the thread open untill the problem was resolved!

Markjosephp (Community Specialist) posted a new reply in Nest Thermostats on 01-30-2023 11:38 AM:

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Re:True radiant in ready mode not learning.

Hi Joeyb1156,   Thanks for completing the form; we have received it. Soon, a member of our upper team will contact you via email. Also, please continue the conversation there, as this thread will be locked within 24 hours.   Thanks, Mark

[CD10]

Mark.  From your response above I take it that Nest thermostats cannot learn how to properly control true radiant heating systems.  If that is the case, will you please refund me for the purchase of a Nest 3rd generation?  I bought it because I fell for the hype in Nest advertising saying the Nest would learn my schedule and save me money.  I wanted a learning setback thermostat. Based on your advertising I thought the Nest would be better than the other brands I have used, but I have found the Nest to be worse at managing the setback than the Honeywell and Emerson thermostats I replaced.  The Nest does not learn how to properly control in-floor radiant heating.  It will hold the temperature if no setbacks are used, but I can do that with a $29 thermostat.

Charles

[Jeff_L1]

We have a vacation cottage using radiant heat in the concrete slab.  Our Gen 2 thermostat overshot horribly -- typically as much as 7 degrees, sometimes as much as 10 degrees.  Thinking it was obsolete, I replaced it with a Gen 3 -- same result.  The documentation all suggests that It should shut the boiler off well before reaching the target temperature, but in fact I've found it still running even at the target temperature.  And there is no "learning."

Being unoccupied during the winter, we've set the thermostat to 55 degrees at 6AM each morning.  Have also fiddled with hourly settings (a suggestion from elsewhere) and max duration set to zero.  Nothing seems to work.  Am very disappointed, since we also have several other Nest thermostats for forced hot air systems which work incredibly well.