Nest calls for heat but furnace does not respond

[billparis]

I have 6 Nest thermostats(6 zones). Today one zone(Nest) called for heat but the furnace didn't respond. The Taco controller is working for the other 5 zones. The Taco relay was swapped and still no heat(no red LED). I swapped out the suspect Nest for a known working Nest and I now have heat in that zone. This means the Nest base is OK, the wiring is OK, the Taco controller is OK and the furnace is OK. The suspect Nest will not work in ANY zone.

I reset the suspect Nest and still won't work(ie. it shows that it calls for heat but the Taco controller says otherwise.)

My conclusion is that the Nest has failed. Any suggestions?

[aatienza]

Hey billparis,

I’m sorry to hear you’re having trouble with this. No worries, we'll check this out. What type of Nest thermostat do you have? Were there any power outages? Do you have a schedule set on your thermostat? Is there a pattern to the heat activating? Is it happening every day, or at the same time each day? Also, what country are you located in?

Looking forward to your response.

Thanks,
Archie

[Markjosephp]

Hello there,

Thanks for assisting, Archie.

@billparis, I wanted to see if you still needed help. I found a helpful article with some troubleshooting steps for when you're having issues with your heating. Please let us know if you have any other questions or concerns.

Best,

Mark

[Jhonleanmel]

Hi everyone,

Just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, I would be happy to keep it open. If there's more we can do, just let me know.

Thanks,
Mel