I have a Day and Night plus 80 gas furnace I did a self test and cleaned the filters
Problem is after about two days it does the following when I set Temp at 80
1 it starts up like it should to the igniter shows a glow like it will ignite the gas 3 the igniter fades out 4 igniter come back on 5 goes back out and then furnace shuts off without even igniting the gas

Any help would help I am no expert and would not want to call in a service person if I can do it myself