Fuel delivery System 

Model No - VR400-vf 

The VR400-vf is used in all condensing or non condensing premix burner applications of large capacity (150 kW to 500 kW) . It consists of a VR400 VA combivalve with pneumatic gas / air regulator assembled directly downstream or upstream of the venturi (the fan mounted downstream maximizes the capacity of the gas valve and ensures full premixing of the gas / air mixture ).

Modulation is obtained by varying the amount of airflow (usually by using a variable speed fan ).  The gas flow will follow the airflow in a predetermined ratio thanks the gas / air pneumatic servo regulator .