Google Nest Thermostat does not heat above 68

[Gsoguy]

All I have been struggling this in the last three months, it has been a big challenge. it never heated over 68° and yes that's cold !!! 

I put my old thermostat in and it works just fine. 
I have a dual zone, single AC unit with heat pump two thermostats. it had seven wires and I didn't really need to use emergency heat, so I was never worried about the seventh wire. 
to be honest, 

i'm posting this I couldn't find any relevant information online, and I thought my AC system was broken. I even had some components replaced that was redundant.

[Ctrammell]

Same issue with ours too. The blower just runs and cold air comes out of the vents. 

[zoeuvre]

Hi folks, 

Uh-oh! I'm sorry to hear that your thermostat never heated over 68°. Let's see what's going on. 

@Gsoguy, when and where did you buy the thermostat? Since putting your thermostat back clears the issue, we can tell that the issue is with your thermostat. You may reach out to the store where you purchase it to have it replaced. 

@Ctrammell, 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 used 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 responses. 

Best,

Zoe