What happens to the FOB when the beer flow stops due to an empty keg?

When the beer flow stops due to an empty keg, the function of the Foam on Beer (FOB) system is to manage the pressurization of the beer lines to prevent excessive foaming and minimize waste. When it detects the absence of liquid beer, the FOB drops, creating a vacuum in the beer line. This vacuum allows for gas, typically CO2 or nitrogen, to fill the line instead of allowing air to enter. By doing this, it eliminates the risk of oxidation and helps maintain the integrity of the remaining beer still in the system, preventing quality degradation. This process ensures that when a new keg is installed, the beer line can quickly fill with the product without introducing excess foaming or air pockets that could negatively affect the beer's characteristics.