Thermostat registering about 10 degrees off

[ThunderHoof]

Everything has been working fine since installing our Nest learning thermostats over a month ago, but over the weekend our main level thermostat has been showing the current temperature as about 10 degrees off.  eg. Thermostat says 72 degrees but house is much warmer (around 80).  I have reset with no luck.  Turning temp down still activates AC unit etc.  

Model: Nest_Thermostat_Display_3.7
Software ver:  6.2-27

No temp sensors added

Sunblock is on and somehow won't let me turn it off?

humidity adjustment is off

[luciaaa]

Hi, @ThunderHoof,

Thank you for reaching out to the community. I apologize that your Nest thermostat is registering about 10 degrees off. I'm happy to help you find a solution.

To better assist you, please provide me with the following information:

• Do you have a conventional or heat pump system?
• Where did you install your thermostat? Did you install it in a room, on a wall, or on a stand?
• Do you have other active Nest thermostats?
• Have you tried any troubleshooting steps?
• Is the problem continuous or under specific circumstances?
• Have there been any recent changes to your HVAC system?
• Have there been any recent power outages or power issues?
• Are you located in Europe or North America?

This information will help to identify the best course of action.

Keep me posted.

Best regards,

Ana

[ThunderHoof]

Thanks for following up.

 - Heat Pump System

 - thermostat upgraded existing thermostat in central hallway on main floor (wall mount)

 - 2 other Nests - nest thermostat upstairs and another nest learning thermostat in the guest house (all on same wifi network and in same home app)

 - Tried every step I could find including restarts and factory reset

 - problem is persistent since a recent wifi system issue where the network was in and out all day

 - no changes to HVAC

 - no power issues

 - located in North America

Thanks!

[AxelD]

Hi ThunderHoof,

Thanks for replying and for providing that information with me. Let’s try some troubleshooting steps that might help you:

• Restart your Nest thermostat.
• Turn on Sunblock
  1. On the thermostat display, go to Settings > Nest Sense > Sunblock.
  2. Select Yes to make sure Sunblock is on.
• Check if the thermostat is near a heat source: Nest thermostats in the U.S. and Canada are typically on a wall. Check if the thermostat is near:
  1. Air vents that direct warm air
  2. Appliances (that includes large televisions)
  3. Electrical outlets
  4. Plumbing (hot water pipes in old buildings are frequently not insulated)
  5. Warm air in the wall
  6. Other potential heat sources
• Cover the wall with a duct seal compound: There’s a high possibility that there’s a heat source behind the wall detected by the thermostat and that’s why they have incorrect temperature readouts. The recommendation would be to apply a duct seal compound on the location where the thermostat is installed to close the filtration on the wall and serve as an insulator.
• Disconnect the thermostat from the Wi-Fi network for 24 hours to monitor the ambient temperature, and contact support afterward. To disconnect the thermostat from the network, select Settings > Network > Disconnect.

Let me know how it works.

Regards,

Axel.