Honeywell VR434FA5031-1000 gas valve DN34

The Resideo VR434FA5031-1000 gas valves are used for gas control in various devices, for example, gas burners and boilers. They have two valves: one opens and closes quickly, and the second can control the gas flow quickly or slowly. There is a pressure control valve between these valves. There are places on the housing for other components, such as pressure switches, which help in controlling these valves.

Technical specifications

• Valve plunger: with Fe 360 coating

• Seals and gaskets: hydrocarbon-resistant types of butadiene-acrylonitrile (NBR) and viton rubber.

• Body material: Aluminum alloy, injection molding

• Strainer: fine mesh mesh (diameter 0.34 mm), AISI 303 steel, can be cleaned by unscrewing the inlet flange screws. Meets the requirements for mesh filters according to EN 161.

• Closing spring: AISI 302 steel

• Minimum adjustment capacity: 1 m3/h.

• Maximum operating pressure: 200 mbar

• Valve classification: Class A + A according to EN 126/EN 161

• Regulator classification: Class C according to EN 126/EN 88

• Supply voltage: mains 230 V~, 50/60 Hz

• Other voltages – on request.

• Ambient temperature: -15 … 60 °C

• The flange kit contains:

1 flange with sealing plug

1 O-ring and 4 screws

1 pressure measuring fitting installed

• Housing: IP 40

Design and principle of operation

Servo-controlled combined gas valves of the VR434FA 5031-1000 series are double fault-tolerant shut-off valves of class A.

The valve is opened by excitation of two-position direct-acting actuators. Each actuator consists of a coil and a locking sleeve assembly. Inside the locking sleeve there is a plunger, which is connected to a rubber valve and can move up and down, thereby opening and closing the valve. The plunger is covered with antifriction material. The flow is regulated by means of a variable stroke of the plunger. A strainer made of AISI303 stainless steel is installed between the inlet flange and the main body. The closing spring of the valve is made of AISI302 stainless steel. Seals and gaskets are made of hydrocarbon-resistant butadiene-acrylonitrile (NBR) rubber according to DIN 3535 and EN 291.

The VR434 FA 5031-1000 valve is a servo system.

The control valve is located between two shut-off valves. When power is supplied to both actuators, the “servo gas” begins to flow through the regulating membrane system. From this chamber, the gas passes into the servo chamber through the intake diaphragm (restriction). The pressure in the servo chamber is regulated by a pressure regulator. The balance between the servo pressure and the pressure under the control membrane determines the opening of the control valve. As soon as the control valve opens, the exhaust pressure generated by the VR434FA5031-1000 series valve will be perceived by the regulator membrane through the feedback channel. When the force generated by this pressure is greater than the value set by the adjusting screw, the control valve opens, somewhat relieving the operating pressure. This reduces the force directed towards the action of the spring of the control valve, allowing the latter to close proportionally. Thus, the control valve limits the exhaust pressure (pressure applied to the burner) to the set level. As a result, the exhaust pressure is continuously maintained by comparing it with the set pressure and changing the position of the control valve accordingly. This means that regardless of the fluctuations in the intake pressure, the exhaust pressure remains unchanged. When disconnected, a small volume of working gas from the regulator and the membrane chamber exits into the main exhaust chamber. The reference pressure feedback channel then regulates the exhaust pressure by compensating for the difference between the air pressure in the combustion chamber and the pressure at the valve. If pressure adjustment is not required, the regulator spring can be blocked by screwing the adjusting screw until it stops or until the pressure regulation stops. In these cases, the full pressure of the “servogas” opens the control valve as much as the pressure drop will allow.

Exhaust pressure adjustment

To adjust the exhaust pressure:

1. Disconnect the pressure feedback (if present).

2. Turn on the power supply for both actuators so that the gas enters the burner.

3. Make sure that the gas is supplied to the unit using a gas meter with a clock mechanism or a pressure gauge connected to the outlet for measuring pressure.

4. Unscrew the pressure regulator cover to access the adjusting screw.

5. Carefully rotate the adjusting screw with a miniature screwdriver until the pressure gauge shows the desired burner pressure. Rotate clockwise to increase the pressure, and counterclockwise to decrease it.

6. If you need to exit the control mode (for example, at low gas pressure), turn the adjustment screw clockwise until it stops.

7. Replace the pressure regulator cover.

8. Restore the pressure feedback connection (if it was disconnected).

Standards

With regard to electrical safety, the Resideo VR434FA5031-1000 gas control units can be used in devices conforming to the European standards of the EN 60335 series, which establish requirements for

The VR434FA 5031-1000 gas regulators also meet all electromagnetic compatibility standards for non-industrial and industrial installations.