No flame sensor on this model! A write up in the manual says this::This furnace hasa hot surface ignition system which features direct ignition of the main burner. The ignitor also ACTS as a sensor for proving main burner ignition??
well now; nothing shows how this occurs;;as the ignitor has only 2 wires running to it and that is at 120 volts when it suppose to be! well this problem never gets to the gas BEING lit! as the HSI never gets red hot on the first to third try;;;
but once the main burner fires it goes well ;;;so however its sensing the flame is working?? many surprises with this furnace!
SOME MAGIC IS OCCURING?? LOL