Honeywell Servo-combi gas valve VR420VA1004-1000

The Honeywell VR420VA1004-1000 is a servo-combi gas valve with a nominal diameter of 20 mm, designed for gaseous fuel systems. It operates with a supply voltage of 230 V at 50 Hz and handles a maximum inlet pressure of 200 mbar, with a flow capacity of 1 m³/h. The valve body is made of aluminum alloy, and it includes a filter with a mesh cell size of 0.34 mm made of AISI 303 steel. It features two main valves (class a + a) and a pressure regulator (class c), with a pressure servo controller and pressure relief valve. The valve is equipped with flanged connections (4 on each side) and comes with a flange kit including a sealing plug, sealing ring, screws, and a pressure measuring fitting.

When selecting a replacement gas valve of this type, ensure the nominal diameter, inlet pressure rating, supply voltage, and frequency match the existing system. The valve must be compatible with the gas type and the ignition system (spark or pilot). Check the flange connections and the included flange kit for proper mounting. The pressure regulation is adjustable via a screw, and the regulator spring can be locked if needed. Verify the ingress protection rating and electrical safety standards meet the installation requirements.

Common failures in this type of gas valve include sticking or leaking due to worn seals (NBR or Viton), which may cause gas odor or pressure instability. The valve plunger coating (Fe 360) can degrade, leading to slow or incomplete closure. If the filter becomes clogged, flow capacity drops, causing burner issues. Electrical failures in the coil or sleeve can prevent valve operation, resulting in no gas flow. Check the pressure feedback connection and ensure the diaphragm is intact for proper regulation.