Nest Thermostat 1.4 have to replace the AA-batteries every 2 weeks

[IDer]

I get the low-battery warning after about 2 weeks of replacing the last pair. I have tried several battery types and checked the C-wire for proper voltage. Attached are some screens from my thermostat and heater

Again, I have checked the C-wire and am getting power through to the thermostat. 

[zoeuvre]

Hi IDer, 

Yikes! I'm sorry to hear that you're getting power issues with your thermostat. M25 error means to troubleshoot Nest Power Connector installation issues. Could you check if your HVAC control board has a Nest Power Connector connected to it? 

I'll look forward to your response.

Best,

Zoe

[IDer]

Zoe, it does not have the Nest Power Connector. If that is required at the time of purchase, it seems it should have been on the packaging. Like I mentioned, it is getting power from the HVAC. 

[Jenelyn_O]

Hi folks,

Chiming in — let's check your Nest Thermostat's battery impedance. Impedance is an indicator that the batteries need replacement. 

Try to put back the original batteries of your thermostat and check your thermostat battery impedance. To do this, on the thermostat display, please go to Settings Battery Battery Status.

If impedance is still higher than 1500 mΩ, put back the new batteries. 

Let us know how it goes.

I appreciate your input, Zoe.

Thanks,

Jenelyn