Furnace blower comes on first

[Plumber69]

Is it normal for a furnace blower to come on for 90secs shut down then inducer runs and everything fires up normal

 

[WorthFlorida]

What model are you talking about? If it is gas or oil fuel, check the thermostat option for Gas or Electric heat. The gas setting allows time for the plenum to heat up before turning on the blower, for electric it is immediate. Check the green wire (fan) at the thermostat. If there is 24v on the green wire then the thermostat is signalling the fan to run. If the fan is running and no 24v's on the green, then it is the control board for the furnace. A test can be disconnect the green wire and then set the thermostat to call for heat. If the fan runs and it doesn't fire up it then the control board.