Heat mode - fan blows prematurely

[Mbernard]

When the temperature to start the heater is reached, the fan immediately blows for about 20 seconds then stops during the heat up mode of my gas furnace. The fan comes back on when the preheat is finished and runs normally from that point.

Auto-scheduling and fan-schedule are both off.

Software v. 6.2-27

[Mbernard · Accepted solution]

This is resolved. The fuel source is automatically set to electric. For a gas furnace (forced air) the fuel needs to be set to gas. To change heat type, on the thermostat, go Settings > Equipment > Continue > Heat type > select "Gas". You can't make the fuel type change on the phone app.