topic Re: Dead Battery in Nest Thermostats

Dead Battery

E78Battery — Thu, 29 May 2025 19:53:07 GMT

I have spent money to find out that the battery in my Nest Thermostat and there is no number so that I can speak with customer service. If anyone knows a working number please get it to me bc they will be replacing this Thermostat or battery.

Re: Dead Battery

E78Battery — Thu, 29 May 2025 19:54:42 GMT

Btw it E74

Dead Battery

E78Battery — Thu, 29 May 2025 19:59:29 GMT

I had spent money to find out that the battery to my Nest Thermostat is dead and there is no number so that I can speak with customer service. If anyone knows a working number please get it to me bc they will be replacing this Thermostat or battery.

Re: Dead Battery

Patrick_Caezza — Thu, 29 May 2025 22:11:38 GMT

@E78Battery

The E74 error code means the thermostat is not seeing power on the Rh wire. If you have a voltage meter, you can check the voltage by measuring between the Rh (red) wire and the C wire if the C wiring is installed. If you don't have a C wire, you can measure between the Rh and either the Y , W, or G, wires. You are looking for 24 VAC.

You can also connect the Rh abd G wires together and the blower should turn on.

If none of these work, then the problem is with the HVAC unit and not the thermostat.