Modine Space heater problem - model PAE 100 AC

[t7694dj]

Went my heater goes to light some times it light just fine and some times it goes to light it will fire but it burns in the tubes where the orifice are and rumble loud nose can anybody help me?

 

[American Locomotive]

That's called rollout. There may be a blockage in the burner, heat exchanger or flue/exhaust pipe. The heat exchanger itself might also be cracked.

 

[t7694dj]

I've took the burner out cleaned and blowed it out with air and shook the lose rust out.

 

[t7694dj]

I took the burner out again and one of the 7 burners had a crack about a 1 inch long
Thanks for your help.

 

[American Locomotive]

That will do it!