Just installed thermostat, no heat.

[Moozer90]

I've had a nest thermostat for years, but my last one stopped working. Just bought a new one, hooked up the wires and no heat. fan is blowing, nest seems to be working, but blowing cold air. I don't have a heat pump, I believe it's a conventional system. Any tips??

[zoeuvre]

Hi Moozer90, 

Uh-oh! I'm sorry to hear that your heat doesn't activates yet the fan blows. Let's sort this out. A few questions:

1. Are you located in North America or Europe?
2. What type of Nest Thermostat do you have?
3. Could you send us a photo of your previous Nest Thermostat wiring configuration and a photo of how you connected the wires to your new Nest Thermostat?
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, ask the customer to 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?

Keep us posted. We're happy to help.

Best,

Zoe