[Fix'n it]

i have owned 2 furnaces. i have noticed they both do this. but it seems a waste of energy.
www.youtube.com/watch?v=S8AI8VZQ-ts
look in between the round parts of the burner at 1:30

 

[user_12345a]

the exhaust from the crossovers gets pulled into the heat exchanger tubes. not a waste.

now if it changes when the fan comes on, there's a problem.

 

[yuri]

The heat stays in your house as the heat exchanger and face plate of the burner area gets hot and the fan picks up that heat.

 

[supers05]

The flame spreader is required to light off correctly. As mentioned before, it's not wasted

Cheers!

 

[Fix'n it]

ok, thanx guys. i figured it was just a somewhat irrelevant flaw that would cost $ to manufacture out. so they didn't, to save $.