Nozzle geometry and performance ensures gas-air mixing for low NOx emissions with premix burners. We achieved 60% reduction on NOx emissions with our venturi NOx burners for a U.K. hospital’s boiler burner while simultaneously improving the turndown ratio to 10:1 during low demand periods, enabling precise heat control during these periods. The quick release nozzle holder allows changing nozzles for different fuel types which improves dual fuel versatility.