I have a 2 wire heat only system, nest won't install

[JakeBoston]

I have a 2 wire system, and when i try to install it on google home it says I need a C wire. Will the google nest not work? I purchased it in Feb 2024. If not, will a 3rd gen Learning nest work with a 2 wire heating only system? I wish these were more transparent before purchasing... Thanks.

[CoolingWizard]

@JakeBoston , although you have a two wire system if that two wires goes directly to a gas valve chances are you have a Milli amp type system, which is not compatible with an thermostat without first installing a transformer in the furnace system

AC Cooling Wizard

[JakeBoston]

Thank you! It does go directly to a furnace. I live in a very old building but just had a new gas furnace installed. I just today bought a 3rd gen nest learning thermostat hoping that would work with my 2 wire set up. Will that work? Thank you for your help, really appreciate it!!

[CoolingWizard]

@JakeBoston ,  can you me the make and model number of your new furnace?

AC Cooling Wizard 

[JakeBoston]

I've attached some photos here, it's a new Burnham independence furnace with natural gas. But our building is 200 years old, and the wiring certainly hasn't been updated in at least the last 40 years. The prior furnace was oil, and the thermostat is an old manual mercury one.