Installed new Nest (gen1 mirror) - No Heat

[dccwong]

1. Installed new Nest this weekend before Christmas, required C wire (was only getting 14v)
2. Connected C wire (now getting 28v)
3. Checked Nest Wiring Info confirming that all wires were connected and "highlighted blue" ( R C W Y G )
4. Battery Status "Good" with voltage at 2.8
5. Turn on Heat, the furnace does NOT turn on. 
   1. We tested old thermostat (upstairs) and the furnace / heat turns on fine
6. Turn on Cool, the A/C does NOT turn on
   1. We tested old thermostat (upstairs) and the A/C/ cool turns on fine
7. Tried with new batteries (voltage showed 3.079v)
   1. Same results, Heat/Cool does NOT turn on
8. Checked Furnace Control Board
   1. All wirings were correct
9. Performed a Factory Reset
   1. Same results, Heat/Cool does NOT turn on
10. No idea what else to do at this point... please help. 

[Markjosephp]

Hello dccwong,

I'm sorry to hear about the issues you're facing with your new Nest Thermostat installation. It sounds like you've done a thorough job of troubleshooting so far. Here are a few additional suggestions that might help:

1. Ensure that your HVAC system is compatible with the Nest Thermostat. You can share with us your HVAC system's make and model.
2. Check Fuse on the furnace control board. There might be a fuse on the furnace control board that could have blown. Check and replace the fuse if necessary.
3. Double-check all the connections on the Nest Thermostat and the furnace control board. Sometimes, a loose connection can cause issues.
   1. Share with us a photo of your old thermostat's wiring setup.
4. Gather the power readouts in the Equipment settings.

Let us know how it goes.

Regards,
Mark