My Nest thermostate stopped heating my home

[Lala4]

I have had no problems with my Nest thermostate.  I have one upstairs and one downstairs. My AC works great using upstairs and downstairs Nest thermostate.  My Nest thermostate works excellent heating the upstairs.  But, my Nest thermostate shows that it is heating downstairs but it's not! I checked equipment and changed to gas but no connection.  Checked equipment and changed to electric, now the vents are barely blowing cold air not heat. Please help?

[Atheos]

This may be an issue with your heater. We recently had to replace a component that opened and let the gas in to heat the air being moved. The nest showed it was on but that it would take hours to increase a few degrees. For us, wasn’t the nest, it was the heater.

[Lala4]

Thank you for your input. But, It's not my heater because upstairs uses the same heating system and it works perfectly fine. 

[Lala4]

Could it be that my Nest thermostat is broken?

[zoeuvre]

Hi folks,

Thanks for chiming in, @Atheos. 

@Lala4, uh-oh! I'm sorry to hear that your heat no longer works in your downstairs. Let's see what's causing this. A few questions: 

1. Are you located in North America or Europe?
2. What type of Nest Thermostat do you have?
3. Is the Nest thermostat newly installed?
4. Does the thermostat screen indicate that it’s actively calling for heating?
5. What type of furnace do you have? (gas, electric, etc.)
6. When did heating last work?
7. Did heating ever work with the Nest Thermostat? If not, did the heating work with the previous thermostat?
8. Did you turn off the power to the HVAC system?
   • Did you recently turn off any breakers?
   • Have you recently experienced a brownout or blackout?
   • Is there a light switch near the heater that controls an outlet?
9. Did you select the correct fuel type?
10. Do the LED lights blink on the HVAC control board? If yes, locate the light.
11. When was the last time you changed the furnace's air filter?
12. Have you experienced extremely cold weather lately?
13. Is this the first notable temperature drop of the year in the area?

I'll look forward to your response. 

Best,

Zoe