Went to use the furnace for the first time this fall last night. Turned on the thermostat and heard the inducer motor spin up. I walked away but then noticed 5 mins later that the furnace wasn't running. Checked to make sure the thermostat was calling for heat. Went downstairs, flipped of the power, turned it back on and the inducer motor spun up again. But, after 20-25 seconds it shut off with no pilot start. I tried this a few times, on/off with the power switch, and it finally took. It worked all of last night. This morning, no heat again. No matter what I tried I can't get it to fire anymore. The inducer motor will run for 20-25 seconds and then just shuts off.
What should I look for to troubleshoot?
Thank you for any help you can offer.