Honeywell Venturi tube VMU400A1010

This venturi tube is a gas and air mixing component for premix gas burners. It maintains a fixed gas/air ratio of 1:1 when the burner load is reduced to 17% of maximum. Modulation is achieved by changing the fan speed. It is rated for a nominal capacity of 400 kW. It is designed to fit the Honeywell VMU400A.

Select a venturi of this class by the burner output, the required pressure differential, and the connection size. The venturi must be matched to the fan's delivered air flow and the gas valve's flow characteristics. When replacing one, check that the flanges, o-ring grooves, or gasket faces are clean and undamaged, and ensure the inlet and outlet diameters align with the mating ducts. Verify that the replacement is intended for the same nominal capacity and gas family (natural gas, LPG, etc.) as the original, because the internal contour is calibrated for a specific gas density and flow range.