Performed annual heating maintenance fair oaks. 12 yr old York split upflow closet. Tested system, system operational. Went thru system safety features. Ok at this time. Checked blower and motor, dirty. Cleaned motor fins. Blower capacitor 10@9.9 ok. Hot surface ignitor @70ohms. Cleaned burners and flame sensor. Took Video to show how ignitor works. Noticed the plenum of the unit is not fully sealed, see pictures. Recommend sealing the plenum. And thinking about adding a dedicated surge protector to your equipment.