Nest 3rd gen thermostat system 2000 heating issue

[Gillade]

I just purchased a 3rd gen nest learning thermostat and I am having a strange issue. My heating system is a System 2000. The only 2 wires connected are the power and heat wire. For some reason my heat will turn on without showing the thermostat turning the heat on.  When I check the heating system it shows it is sending heat to that zone but is not calling for heat. Never had this issue with my other thermostat and seems to be an issue with the nest thermostat. Not sure what else to do. 

[Guarcax]

Hi there!

Thanks for posting in the community. 
I’m sorry for the inconvenience that this Nest Thermostat Learning 3rd generation may cause to you. I understand you just installed the Nest Thermostat and that the HVAC is heating, but the Nest thermostat is not showing that activity.

Upon checking here the information, it seems that some systems are not compatible with our thermostat. As a first step, you should check the compatibility of your HVAC system using the next website: Thermostat Compatibility.

If it is compatible, you can follow the next steps:

1. Turn off power to your system at the fuse box or system switch. This will help prevent damage to your system and help keep you safe.
2. Pull off the Nest thermostat display.
3. Check that all connectors that have wires are down (see picture). 
4. If needed, re-insert wires so that the connector button stays fully pressed down. If the button isn’t down, your Nest thermostat won’t know there’s a wire in the connector. 
5. You may need to re-strip and straighten the wire ends so that they can be fully inserted into the Nest base’s connectors.

Please check the following articles for further information: Learn about the common or C wire and Nest Power Connector.

Tell me how it goes.

Regards,

Daniel.