Nest to Milivolt System Resistance

[ansontzy]

Hi All, 

I have a google nest thermostat that is currently wired to a milivolt williams gas heater with a flame/pilot light and a transformer C wire. In the past few weeks, it stopped working when it used to, and when the electrician came by, he said it was because the resistance on the thermocouple is equal to the resistance the nest is giving (or something along those lines), which results in the furnace not completing the circuit and not heating up. He advised me to get a regular honeywell simple thermostat, which I agree with since the wall heater isn't meant to work with the nest. However, I wanted to seek advice from the community on ways to get it to working again since it used to. Not sure what I need to do here. Thanks again!

Not sure how to upload images so here is the drive link to the transformer and the wiring https://drive.google.com/drive/folders/1myJBsqvIkM0lD3zbyhJnmXE4-eJqpJvp?usp=sharing

[Patrick_Caezza]

@ansontzy 

That wiring is not going to work and could damage the Google Nest Thermostat.

You need the Google Nest Power Connector, 24vac external transformer, and possibly a relay.

Try this wiring

  

[TuTall223_Bob]

Patrick, I have a question, I’ve had the Nest thermostat for a year plus on my heat pump HVAC system. The weather is changing getting cooler, and A/C hasn’t turned on for a week. The screen went off red LED flashing. I charged Mest and it worked for a day. Yesterday it wouldn’t turn on the heat in the morning.  Is the a firmware update that might be using more battery now, or something else?