Standard Furnace model CUB100A948C4 Found the fan running continuously this morning with no heat. Turned heat off from thermostat, but blower kept running. Changed filter (per troubleshooting section) and put heat to the on position. Funace lit and ran until I lowered the temp on thermostat. When I tried to get it to run again (raised the temp again) it lit but kept shutting itself down right away.

Try cleaning the flame sensor. It is usually located and the end of the main burner assembly OPPOSITE the ignitor.