Pilot operated regulators provide accurate, responsive pressure control for natural gas distribution, commercial facilities, industrial processes, and other demanding applications. By using a smaller pilot regulator to control a larger main valve, these devices can manage substantial flow rates while maintaining more consistent pressure as operating conditions change.

Unlike direct-acting regulators, which rely primarily on a spring and sensing element to move the main valve, a pilot operated pressure regulator uses a pilot control system to adjust loading pressure and regulate flow. This allows the main valve to respond to relatively small changes in system pressure without requiring the sensing element to directly overcome the full main valve operating forces.

Pilot operated regulators are available in both pressure reducing and back pressure/pressure relieving configurations. Understanding how these designs work, their advantages, and their application requirements can help you select the right pressure control solution for your system.

What Is a Pilot Operated Regulator?

A pilot operated regulator is a pressure control device that uses a smaller, pressure-sensitive pilot regulator to control the operation of a larger main valve. The pilot monitors system pressure and adjusts the loading pressure acting on the main valve's diaphragm or actuator.

This arrangement allows a relatively small pilot to control a much larger flow capacity. Rather than relying solely on a spring to directly position the main valve, the pilot system uses available process pressure to help operate it.

Depending on its configuration, a pilot operated regulator can be designed to:

• Reduce higher inlet pressure to a controlled downstream pressure.
• Maintain a desired upstream pressure by adjusting flow through a back pressure regulator.
• Provide modulating pressure relief in applications where that function is appropriate.
• Respond to changing flow demands while maintaining pressure near a desired set point.
• Handle large flow volumes without sacrificing pressure-control performance.

Pilot operated regulators are sometimes called pilot controlled regulators or pilot-operated gas pressure regulators. The terms generally describe the same basic control principle, although individual regulator designs and pilot arrangements can vary.

How Does a Pilot Operated Pressure Regulator Work?

A pilot operated pressure regulator works by using system pressure and a smaller pilot valve to control the position of the main valve.

The pilot senses the pressure being controlled and responds to deviations from the desired set point. It adjusts loading pressure on the main actuator, causing the main valve to open or close as needed.

Three Main Components of a Pilot Operated Regulator

• Pilot Regulator: Senses the controlled pressure and adjusts the loading pressure supplied to or released from the main valve actuator.
• Main Valve: Controls the primary flow of gas or fluid through the regulator.
• Actuator and Sensing System: Uses diaphragm or piston forces, loading pressure, and pressure feedback to position the main valve.

Many designs also incorporate control tubing, restrictions, filters, and other accessories that influence regulator response and stability.

Step-by-Step Operation

Although the exact sequence depends on the regulator design, a typical pilot operated pressure reducing regulator works as follows:

1. Pressure is sensed: The pilot monitors downstream pressure through an internal or external sensing connection.
2. The pilot responds: When downstream pressure changes relative to the set point, the pilot adjusts the main valve's loading pressure.
3. The main valve moves: Changes in loading pressure cause the main valve to open or close.
4. Flow is adjusted: The regulator increases or decreases flow to bring downstream pressure back toward the desired set point.
5. Pressure stabilizes: The pilot continuously modulates the main valve as operating conditions change.

For a pilot operated back pressure regulator, the same general pilot-control principle applies, but the regulator senses and controls upstream pressure instead of downstream pressure.

What Are the Benefits of Pilot Operated Regulators?

Pilot operated regulators are often selected when an application requires greater flow capacity, tighter pressure control, or improved performance under changing operating conditions.

Actual performance depends on the regulator model, pilot configuration, pressure differential, operating conditions, and proper sizing.

Pilot Operated vs. Direct-Acting Regulators: What's the Difference?

Both pilot operated and direct-acting regulators provide automatic pressure control, but they use different methods to position the main valve.

Neither design is automatically better for every application. A direct-acting regulator may provide all the performance required with less complexity, while a pilot operated regulator may be a better fit when higher capacity or more precise control is needed.

What Types of Pilot Operated Regulators Are Available?

Two major categories of pilot operated pressure regulators are pressure reducing regulators and back pressure regulators/relief valves.

Pilot Operated Pressure Reducing Regulators

A pilot operated pressure reducing regulator maintains a desired downstream pressure by automatically adjusting flow from a higher-pressure supply.

When downstream pressure falls below the set point, the pilot system responds by adjusting loading pressure so the main valve can open further. When downstream pressure rises, the pilot adjusts the loading pressure to move the main valve toward the closed position.

These regulators are commonly used where a high-pressure natural gas supply must be reduced to a stable, usable pressure for downstream equipment or distribution systems.

Common applications include:

• Natural gas distribution and city/district gate stations
• Large industrial and commercial boilers
• Industrial furnaces and ovens
• Gas engines and compressors
• Commercial and industrial fuel gas systems
• Large-volume gas service applications
• Fixed-factor billing and service regulation

Explore BelGAS Pilot Operated Pressure Reducing Regulators.

Pilot Operated Back Pressure Regulators and Relief Valves

A pilot operated back pressure regulator maintains a desired upstream pressure by automatically adjusting flow through the main valve.

When upstream pressure rises above the selected set point, the pilot responds by changing the loading pressure on the main valve, allowing it to open and pass additional flow. As upstream pressure decreases, the pilot moves the main valve toward the closed position.

These regulators can provide high-capacity back pressure control and modulating pressure relief, depending on the design and application.

Common applications include:

• Gas gathering systems
• Gas separators
• Fuel gas pressure relief
• City and district gate relief or bypass systems
• Compressor stations
• Industrial process pressure control
• Plant air systems
• High-flow pressure relieving applications

Although some products are designed for both back pressure regulation and relief service, a pilot operated regulator should not automatically be treated as a certified safety relief valve. Applications requiring code-compliant overpressure protection must use appropriately rated and approved devices.

For a more detailed explanation of upstream pressure control, read our article Back Pressure Regulators: What You Need to Know.

Explore BelGAS Pilot Operated Back Pressure/Pressure Relieving Regulators.

Pilot Operated Pressure Reducing vs. Back Pressure Regulators

The most important difference between these regulator types is which side of the valve they control.

If your system needs a stable pressure after the regulator, a pressure reducing design is generally appropriate. If your system needs to maintain pressure before the regulator, a back pressure design may be the better choice.

Common Applications for Pilot Operated Natural Gas Regulators

Pilot operated natural gas regulators are widely used in commercial and industrial systems where pressure accuracy and high flow capacity are important.

How Do You Choose the Right Pilot Operated Regulator?

Proper selection begins with understanding the system's operating conditions. Choosing a pilot operated pressure regulator based only on pipe size or maximum inlet pressure can result in poor control, instability, or insufficient flow capacity.

Important factors include:

• Regulation Function: Determine whether you need downstream pressure reduction or upstream back pressure control.
• Process Media: Identify natural gas, air, or another compatible gas or fluid.
• Inlet Pressure: Establish minimum, normal, and maximum supply pressures.
• Desired Set Point: Identify the pressure the regulator must maintain.
• Outlet Pressure: Determine the downstream operating pressure and its expected variation.
• Flow Requirements: Calculate minimum, normal, and maximum flow rates.
• Available Pressure Differential: Confirm sufficient pressure differential for proper pilot and main valve operation.
• Accuracy Requirements: Evaluate acceptable droop, buildup, and pressure variation.
• Pilot Configuration: Select the pilot type and control arrangement suited to the application.
• Temperature and Materials: Verify compatibility with process temperature, media, and environmental conditions.
• Connection Requirements: Consider NPT, flanged, and other installation requirements.
• Safety and Compliance: Evaluate overpressure protection, applicable codes, and any required approvals.

Regulator sizing should also account for potential low-flow instability, lockup performance, and the response of the complete pilot and main valve assembly.

BelGAS Pilot Operated Pressure Reducing Regulator Options

BelGAS offers multiple pilot operated pressure reducing regulator designs for commercial, industrial, and natural gas distribution applications.

View All BelGAS Pilot Operated Pressure Reducing Regulators.

BelGAS Pilot Operated Back Pressure and Relief Valve Options

For applications requiring upstream pressure control or modulating relief, BelGAS offers pilot operated back pressure and pressure relieving regulators.

These products offer options for systems where a conventional direct-acting regulator may not provide the required combination of capacity and pressure-control performance.

View All BelGAS Pilot Operated Back Pressure/Pressure Relieving Regulators.

When Should You Consider a Pilot Operated Regulator?

A pilot operated pressure regulator may be the right solution when:

• Your application requires high flow capacity.
• Pressure must remain relatively stable as demand changes.
• A direct-acting regulator cannot meet the required accuracy.
• Reduced pressure droop or buildup is important.
• You are controlling natural gas pressure for large commercial or industrial equipment.
• Your system operates across a broad range of flow conditions.
• You need pilot-controlled downstream pressure reduction.
• You need high-capacity upstream pressure control or modulating relief.

However, pilot operated designs are not necessary for every application. Simpler direct-acting or pilot-loaded designs may offer a more economical solution when operating requirements allow.

Why Choose BelGAS for Pilot Operated Pressure Regulation?

BelGAS provides pressure control solutions for commercial, industrial, and natural gas applications, with product options designed around varying pressure, capacity, and operating requirements.

• Pressure reducing and back pressure/pressure relieving designs
• High-capacity regulator configurations
• Multiple pilot arrangements and pressure ranges
• Solutions for natural gas distribution and industrial equipment
• Direct-acting, pilot-loaded, and pilot-operated alternatives
• Product selection and application engineering support
• Regulator sizing resources to help identify appropriate solutions

Explore the BelGAS Regulator Sizing Wizard or contact our team to discuss your application requirements.

Frequently Asked Questions About Pilot Operated Regulators