Hello and thanks ahead of time for any responses. I am the second owner of this home with a 13 year old Amana Distinctions furnace that has started to trip the flame blow back safety switch and throw a code of 6 blinking led. I have had the unit opened while running and also while viewing in the peep hole, I do not see the flame blow back that several youtube videos have shown. Exhaust pipe is clear the best I can tell (plenty of steam /exhaust when furnace is running). My initial assumption was the heat exchanger tube cracked or corroded out. We do have some corrosion in several areas and at times there will be puddles that form on the floor. So to test this with it tripped the furnace fan will continue to blow and I tried a match stick flame in each of the flame/heat exchanger tubes. The match stick flame did curve back but not violently as if being blown out due to a crack in the heat exchanger. So from my non-professional thoughts it doesn't seem to be a cracked heat exchanger issue. With the furnace running, I noticed that there appears to be flames coming out of the what appears to be crimped wing like side portions of the burners. I don't know the terminology or if this is normal flame behavior exiting the burner tube. I attached a picture of a burner with some hand drawn red flames at the place of where I see flames. These flames certainly are splashing out on the front surface of the exchanger but again I do not know if this is normal behavior. I will attach a pic of the actual flames. Sorry its a crappy cell phone pic. I am tempted to purchase new burners as these are original and a HVAC guy who inspected the furnace when we bought the house had said it appeared that the furnace had been running while propane tank was empty due to sooting on burner tubes. He pointed out the corrosion and said it was common with this furnace and believed there was some warranty on it but we were outside that timeframe. So any suggestions would be appreciated.