The heat does not turn on using my 3rd gen Google Nest Thermostat

[JChen1]

I have an issue where the heat does not turn on. It is set to gas, forced air, and fan on. The fan doesn't even turn on sometimes.

I have also tried setting it to electric - forced air in case it uses electricity. Neither appears to warm up my house.

[Joshvalentine]

I’m having the same issue

[JEGGY]

I am also experiencing this issue. I'm searching online for this exact issue. It was working fine before. I do see that my thermostat updated on Nov 2nd which was two days ago.

[sebarger]

By fan "on", do you mean "Activate"? I have an issue where my fan won't come on automatically and have researched that this is because my HVAC system relies on my thermostat to tell the fan to come on. The Nest default setting is apparently to rely on the furnace to tell the fan or a setting of "Don't Activate".

How did you get to this screen? When I go in through Pro Setup and click on W1, I only see Type (Conventional Heating), Source (Oil in my case), Delivery (forced air), and no Fan setting!

[sebarger]

After going back and forth with Google support, we figured out a workaround for my setup. Go through Pro Setup menu, click on W1 (power), and change the Source from Oil to Gas. Now the the Fan option will appear allowing you to set it to "Activate". No idea why the Fan option doesn't appear for Oil as I'm sure there are a lot of people with oil furnaces and forced air 🤔