Honeywell Gas valve VK4100A1002U

The Honeywell VK4100A1002U is a combined gas valve for burner control and ignition systems, providing safe ignition, flame control, and gas flow regulation for pilot and/or main burners. It features regulation of gas and air with a 1:1 ratio, operates within an ambient temperature range of -15 to 60 °C, and has a maximum working pressure of 45 mbar. The valve has a flanged connection thread, with inlet and outlet diameters of 18.6 mm, and a side outlet orientation. It includes a pilot gas connection diameter of 4 mm, a diaphragm diameter of 2.8 mm, and a pressure sensor pipe diameter of 0.5 inch. Nominal inlet pressure is 25 mbar, with maximum inlet pressure of 60 mbar, and back pressure on the 1st valve is 50 mbar. The compression fitting is 4 mm, and ambient pressure is 1013 mbar.

Parts of this type are selected by matching the connection thread and diameters to the existing piping, ensuring the inlet and outlet sizes align with the burner manifold. The valve must be compatible with the gas type and pressure requirements of the system. Installation involves checking the orientation (side outlet) and securing flanged connections. Before ordering, verify the maximum working pressure and inlet pressure ratings against the system's specifications.

Common failure modes for gas valves of this kind include failure to open or close properly, leading to no gas flow or continuous flow. Symptoms may include burner ignition failure, unstable flame, or inability to modulate gas pressure. Check for electrical continuity, diaphragm integrity, and blockages in the pilot gas connection or pressure sensor lines.