How to check a flame roll out?

Answer 1

warning: flame roll out can cause serious injury

1) turn service switch off at the furnace 2) adjust thermostat so set point is 5-6 degrees above room temp, set t-stat for heat, and set fan to auto 3) remove ignition compartment door of the furnace as opposed to the door enclosing the indoor blower motor 4) turn the furnace service switch back on 5) do not look directly at the combustion burners as flame will shoot out of the burner compartment 6) observe the ignition

finally proper ignition is confined to the area intended for combustion, with a blue flame. a roll out will cause the flame to ignite beyond the burners and may even blow beyond the blower compartment. further, a roll out can persist beyond the initial ignition sequence.