Removing the Burner
Whenever you receive a work order to repair a burner, the first step is to inspect the flame patterns. Always check draft to make sure that the furnace is operating at negative pressure before opening the peepholes to avoid getting burned by hot gases. Even after checking draft, always stand to the side of the viewport and carefully open it.
Before removing the burner, you should gather all of the pertinent documentation such as the general arrangement drawing to understand how the burner is assembled and how it should be aligned. The documentation will also show critical tolerances which need to be maintained.
When removing the burner, all of the parts should be match-marked to maintain the alignment and facilitate reassembly.