I have a 26 ton Aaon rooftop unit that is 3 years old and has since installation made excessive burner noise when the burners initially come on. The burners come on full for the initial 45 second start up and then modulate down. Nothing has been modified on the unit, the gas pressure, orifices, alignment and blowers are all checked out. The unit sounds like a jet engine on the roof. Aaon says its normal.
Any help would be appreciated.