Method, system and apparatus for firing control

A method of controlling the air to fuel ratio in a burner comprising a venturi assembly, the method comprising:

• admixing air and a fuel in a venturi assembly, the venturi assembly having:
• an outer venture surface;
• an upstream air inlet,
• a converging portion with a primary injection fuel inlet,
• a throat portion downstream from the converging portion,
• a diverging portion downstream from the throat portion,
• an outlet, and
• a secondary gas inlet disposed on the outer venture surface and downstream from the converging portion and upstream from the outlet,
• the admixing comprising:
• introducing fuel into the primary injection fuel inlet,
• receiving air through the air inlet by inspiration, and
• feeding a gas through the secondary gas inlet,
• wherein the flow rate and content of the gas fed through the secondary gas inlet being selected to result in a desired air to fuel ratio through the outlet.