Honeywell VR425MA1002-0000 gas valve DN25

The Resideo VR425MA1002-0000 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

Honeywell VR425MA 1002-0000 combined gas valves are controlled by devices with two positions, opening and closing the valves. Each device includes a coil and a sleeve with a plunger connected to the valve and coated with a low-friction material.

They act as a system where spring pressure keeps the valves open. The basis is a pressure regulator with a relief valve built into the regulator membrane. The diaphragm controls the control valve.

The power supply to both devices forces the gas to pass through the diaphragm into the system and the regulator. This creates a “servo gas” that lifts the membrane. When the control valve is open, the pressure created by the gas regulator is regulated by the diaphragm through feedback.

If the pressure of the diaphragm is higher than the set one, the control valve partially reduces the pressure, allowing it to close. This keeps the output pressure at a constant level, regardless of changes in the input pressure. When disconnected, a small volume of gas from the regulator is discharged.

The adjusting screw is used when pressure changes are necessary. Otherwise, the full pressure of the “servogas” determines the position of the control valve based on the pressure.

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 VR425 MA 1002-0000 gas control units can be used in devices conforming to the European standards of the EN 60335 series, which establish requirements for

The VR425MA 1002-0000 gas regulators also meet all electromagnetic compatibility standards for non-industrial and industrial installations.