Spiders, mud wasps, and other insects can build nests in the burner tube. This will cause poor combustion, delayed ignition or ignition outside combustion tube.
Listen for a change in burner sounds or in flame appearance from a hard blue flame to a soft lazy flame or one that is very yellow. These are indications of an obstruction in burner tube (C).
1
Remove air shutter screw (A) and slide air shutter (B) down burner tube.
2
Run a flexible wire brush down burner tube (D) until it is visible at end of burner tube.
3
Vacuum burner where it enters combustion tube.
4
Return air shutter to original position and replace screw.
5
The orifice, burner tube and shutter must be aligned so that the shutter is not binding on the air tube.