Nest device turn on too short

[Tpham]

 

Hi, I am using a nest thermostat e, and I notice that alot of time the nest device turn on my central air system for less than 8 minutes per on cycle.  My central air is definitely not oversized, or improperly ducted.

With further investigation using openhab log (a home automation system), I noticed that there are times the thermostat would try to cool my house by less than 1/10 of a degree, which would explain why it is happening.  This is shown in the third line from the bottom in the attached pix, the thermostat was trying to cool the house by 0.01 degree.  As a temporary remedy, I had to automate my home automation system to not short cycle the ac by setting the target temperature by another 1.2 degree cooler.

I would like to know if Google or other users know about this issue?  Having this issue is very bad for the ac compressor, and I hope this is not affecting million of users out there.

Ideally, it would be nice for Google to use machine learning to prevent short cycling.  In the time being, it would be nice for users to be able to adjust minimum cool temp threshold, 0.3 to 3 degrees or so.

 

[Markjosephp]

Hello Tpham,

Thank you for taking the time to let us know about your inquiry. I'd love to know more about this.

It appears that you're experiencing power issues as your thermostat receives less power than it needs. To isolate: could you please share with us a photo of your thermostat's wiring? Are you getting any power reports or message codes? Also, gather the power readings in the Technical Info settings.

I'll look forward to your response.

Best,
Mark

[Tpham]

• Attached files are images of the system and the wiring.  I have not received any info about power outages.  Just so you know, I ran the thermostat 1 hour straight last and it did not stop due to power issues.  

My nest thermostat is reporting statuses to nest sdm pubsub service (Google cloud), let me know if you need access to monitor the device.  Otherwise, I can supply logs if you are serious about investigating into this issue.  

As an work around, I always have my home automation system run the ac a little bit longer and it seems to work well.  Furthermore, I would be nice if you can tell me the business logic of turning on an ac unit for cooling once ambient temperature reaches setpoint.  Thanks

[Tpham]

 

 

[zoeuvre]

Hi folks, 
 

@Tpham, chiming in — can you help us with the power reading of your Nest Thermostat? You can view it from its Settings, then look for Power Info. 
 

I’ll look forward to your response. 
 

I appreciate your help, Mark. 
 

Best,

Zoe

[Dan_A]

Hey there,

I wanted to follow up and see if you still needed help. Please let me know if you still have any concerns or questions from here, as I would be happy to take a closer look and assist you further.

Kind regards,

Dan

[Dan_A]

Hello again,

We haven't heard from you in a while, so we'll be locking this thread if there is no update within 24 hours. If you need assistance or want to discuss topics, feel free to start a new thread.
 

Cheers,

Dan