In modulating burners, the gas flow can follow the air flow via a gas-air ratio regulator.
Air reference signal
The pressure from the fan, venturi, or combustion chamber is used as a reference so that the gas valve modulates the flow accordingly.
Goal
To maintain a constant and correct air-gas ratio throughout the entire modulation range.
Impulse lines
The lines carrying the pressure signals must remain clean, airtight, and free of condensate.
Adjustment
The final ratio is verified using a flue gas analyzer at low, medium, and high fire.
