Nest 3rd generation learning thermostat on 4 wire system fails heat and blower tests.

[Lproff]

I just installed Nest 3rd generation learning thermostat on 4 wire system, and it fails heat and blower tests. 

The original thermostat was wired W, Rh (jumper to Rc), G, and Y. See photo. 

 

I followed Nest app instructions and connected Y1, W1, G, & Rh.

 

I close everything up, run the test for heat - - nothing. Same with the blower test. It's too cold to run the AC test. 

Any thoughts? My HVAC guy thinks I need C wire, but I'm not sure. 

Thank you 

[Patrick_Caezza]

Pull the front off and connect it to a USB cable and charge it overnight.

Your wiring looks good and the 3rd Gen Learning thermostat will work without a C wire.

[Lproff]

Thank you. I did as suggested and re-connected the wires. The system test did not turn the heat or blower on. I decided to just skip the tests and see what happened.  The thermostat is working and the house is heating. Not sure why the system test did not work.

[Jenelyn_O]

Hi Lproff,

Chiming in — I'm glad that it turns out that there's nothing wrong with your system. I'm sorry that the Nest Thermostat fails during setup, we’re always looking for ways to improve and we’ll take this as feedback. Let me know if you still have questions and concerns otherwise, I'll be locking this thread after 24 hours.

Best,

Jenelyn