Nest will not turn on the heat.

[chrger1970]

I installed my new Nest today and love the way it looks and that its hooked up to my Wifi. However, after setting it up I come to find out that the heat would not come on. The Nest was saying it was coming on and that the fan was on, but it was not. It was however telling me the temp outside and it was hooked up to my network and everything looked good. I have a 4 wire setup and there is no wire for the C wire on the thermostat. I had to put my old thermostat on and the heat came right back, and so you know, there also is no C wire for the old thermostat. What should I look for to remedy this problem? Thank You for any help. 

[zoeuvre]

Hi chrger1970, 

Yikes! I'm sorry to hear that your newly installed Nest Thermostat is not turning on your heat. Let me take a look at this for you. 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. Did you use the Compatibility Checker tool to confirm the thermostat's compatibility. 
5. Does the thermostat screen indicate that it’s actively calling for heating? 
6. What type of furnace do you have? (gas, electric, etc.)
7. When did heating last work? 
8. Did heating ever work with the Nest thermostat? 
9. Did the heating work with the previous thermostat? 
10. Did you turn off the power to the HVAC system? 
11. Did you recently turn off any breakers?
12. Have you recently experienced a brownout or blackout? 
13. Is there a light switch near the heater that controls an outlet? 
14. Did you select the correct fuel type? 
15. Do the LED lights blink on the HVAC control board? If yes, locate the light. 
16. When was the last time you changed the furnace's air filter? 
17. Have you experienced extremely cold weather lately?
18. Is this the first notable temperature drop of the year in the area?

I'll look forward to your response. 

Best,

Zoe