High Capacity Series Remote Pilot Reg Port Sizes 3/4" to 2"; Flow to 4000 scfm (113280 l/min)

Product Overview

The ROSS Controls is the high-capacity segment of the ROSS remote pilot regulator family, providing remote pressure set point control in large-bore inline configurations from 3/4" to 2" port sizes in standard variants, and up to 3" port size in extended high-capacity variants. With maximum flow capacity reaching 4000 scfm (113280 l/min) through the largest 3" configuration, the series is designed for central supply stations, production main headers, and large-volume compressed air systems where both high flow capacity and remote pressure adjustment capability are simultaneously required.

Remote pilot operation allows the series main regulator body to be installed in any location in the compressed air distribution system, including physically inaccessible locations, hazardous environments, or high-temperature areas, while pressure set points are adjusted via a small pilot regulator connected to the main body's pilot port. The pilot signal line can be routed over substantial distances, giving operators and control systems full pressure control authority without proximity to the main body installation point.

The Series is offered in four distinct physical configurations: standard inline (diaphragm, 3/4" to 1-1/2"), high-relief inline (for large pressure differentials, 3/4" to 1-1/2"), extended large-bore (diaphragm, 1-1/2" to 2"), and extended high-capacity (diaphragm or piston, sizes to 3"). Both diaphragm and piston construction options are available in the high-capacity extended configurations, providing either high sensitivity (diaphragm) or high durability in contaminated or pulsating flow environments (piston).

With maximum inlet pressure of 300 psig (21 bar) standard and 400 psig (28 bar) premium, and outlet pressure ranges to 200 psig (14 bar) standard - depending on pilot regulator setting - the series covers the broadest range of large-volume remote pressure regulation requirements in the ROSS FRL product family.

Key Engineering Features

• Highest Flow Remote Pilot Regulation - Flow capacity reaching 4000 scfm (113280 l/min) through 3" port extended configurations, representing the highest flow capacity in the ROSS remote pilot regulator family and enabling central supply regulation for entire production facilities.
• Multiple Construction Options - Available in diaphragm construction (high sensitivity, accurate regulation) and piston construction (high durability, contamination tolerance) in the extended high-capacity configurations, allowing selection based on application priority.
• Four Variant Levels - Standard inline (740 scfm max, 3/4"-1-1/2"), high-relief inline (700 scfm, high pressure differential), large-bore extended (850 scfm, 1-1/2"-2"), and high-capacity extended (4000 scfm, to 3") configurations address the full range of large-volume remote pilot applications.
• Remote Pilot Port - 1/4" NPTF pilot port on all variants accepts the remote pilot regulator output, allowing operators and control systems to command downstream pressure from any accessible location regardless of main body installation point.
• Self-Relieving Design - Standard self-relieving diaphragm construction allows downstream pressure to vent through the main body when pilot set pressure is reduced, preventing pressure buildup above the commanded set point.
• Inline Installation for Large Pipe Sizes - Designed for inline installation in 3/4" through 3" compressed air piping systems, the series integrates directly into existing large-bore distribution headers without modular manifold structures.
• Extended Temperature Rating - Rated to 175 F (79 C) ambient and media temperature in standard and extended configurations (Nitrile seals), enabling installation near process equipment, in warm outdoor environments, and in hot utility areas.
• High Inlet Pressure Capability - Standard configurations accept 300 psig (21 bar) inlet; premium high-relief variants extend to 400 psig (28 bar), accommodating high-pressure storage and transmission system headers.
• Fluoroelastomer Seal Option - Fluoroelastomer seals available in the 3" high-capacity extended configuration, providing chemical resistance for applications where compressed air contains trace solvents, oils, or other chemicals incompatible with Nitrile.
• NPTF and G Thread Standards - All port sizes and variants available in both NPTF and G (BSPP) thread standards for worldwide installation compatibility.

Technical Specifications

General Specifications

Temperature Ratings

Standard and large-bore extended variants with Nitrile seals are rated to 175 F (79 C). Extended high-capacity variants with Fluoroelastomer seals extend chemical compatibility; consult ROSS Controls for temperature limits on Fluoroelastomer configurations.

Flow Performance Data

Flow performance varies significantly by variant and port size. Maximum values shown below represent each variant's highest port size rating. All values at rated inlet pressure.

Certifications & Compliance

Typical Applications & Industries

Central Compressed Air Supply Headers

• Facility-wide central supply station regulation at the main distribution header, where the series extended 3" variant (4000 scfm) serves as the primary pressure reduction and regulation point for entire manufacturing plants, reducing storage receiver or compressor outlet pressure to facility working pressure with remote set point capability.
• Building-level compressed air header regulation for large industrial facilities where a central operator station commands all building zone pressures through remotely piloted Series units at each zone header.
• Multi-building campus compressed air distribution regulation where Series high-capacity units serve as regulating stations at branch header takeoff points, all controlled from a central utilities management system via I/P transducers on the pilot signal lines.
• Compressor station outlet regulation serving large reciprocating or centrifugal compressor installations, where the series reduces compressor discharge pressure for distribution while allowing remote pressure trim adjustment from the compressor control room.
• Nitrogen, dry air, or specialty gas header regulation in industrial gas distribution systems where high flow capacity and remote set point control are both required.

Large Process Industries

• Chemical plant instrument and utility air header regulation with remote set point control from the central control room, providing adjustable working pressure across the plant without field access to each regulator location.
• Petroleum refinery compressed air supply regulation for process area distribution, with main bodies in the process area and pilot adjustment from the control room or designated operator stations in safe areas.
• Petrochemical plant pneumatic actuated control valve supply regulation where the series serves as the main header regulator for large valve and actuator supply networks, remotely controlled from distributed control system (DCS) output via I/P pilot transducers.
• Offshore platform and marine vessel compressed air supply regulation where regulator bodies are installed in confined machinery spaces and remote adjustment is performed from the bridge or control room.
• LNG facility and cryogenic plant utility air supply regulation with Fluoroelastomer seal options for chemical compatibility with air streams potentially containing trace hydrocarbons.

Steel Mill and Heavy Industry

• Steel mill process air supply regulation for rolling mill actuators, hydraulic system accumulator charging, and process cooling systems, where the extended 175 F (79 C) temperature rating accommodates the hot-mill environment near the regulators.
• Blast furnace and steelmaking process area compressed air supply, where high flow capacity (4000 scfm for the 3" extended variant) matches the peak demand of large multiple-actuator systems.
• Mining and mineral processing compressed air supply regulation for large-bore conveying, blasting, and process air systems, with remote adjustment from surface control rooms for underground installations.
• Power generation facility compressed air supply regulation for instrument air headers serving boiler controls, turbine actuators, and process isolation valves.
• Pulp and paper mill compressed air regulation for large-scale headbox actuation, forming roll positioning, and press section actuator supply.

Automated and Programmable Pressure Control

• Automated production systems where I/P electro-pneumatic transducers driven by PLCs or DCS systems provide the pilot signal to the series, enabling recipe-driven, program-controlled large-volume pressure regulation without manual intervention.
• Test facility large-volume pressure control for aerospace, military, or industrial test chambers where precisely regulated high-flow air supply is required at remotely programmable pressures.
• Large spray coating and surface treatment line supply regulation where multiple Series high-capacity units serve different zones at different pressures, all remotely adjustable from the facility control system.
• Tire manufacturing and vulcanization press supply regulation where the series serves as the main supply regulator for high-flow steam-heated mold actuation and curing press systems.

Ordering and Model Number Configuration

The ROSS is available in four distinct configurations: standard inline, high-relief inline, large-bore extended, and high-capacity extended. Select the appropriate variant based on required port size, flow capacity, and pressure differential requirements. Contact ROSS Controls for complete model number configuration for non-standard variants.

Select variant based on port size and flow capacity: Standard Inline for 3/4"-1-1/2" at up to 740 scfm, High-Relief Inline for high pressure differential applications at the same port range, Large-Bore Extended for 1-1/2"-2" at up to 850 scfm, High-Capacity Extended for 3" at up to 4000 scfm.

Fluoroelastomer seal option (model 5X00B9021 and C5X00B9021) is available in the 3" extended configuration only. Standard Nitrile seals are used in all other configurations.

G (BSPP) thread models are prefixed with C. Verify thread standard required for all port connections including the pilot port.

Pilot port is 1/4" NPTF on all variants. A pilot regulator (ROSS FRL or equivalent) is required separately.

For special pressure ranges, piston construction options, or sizes not listed, contact ROSS Controls for application-specific configuration assistance.

Variant Selection Guide

Standard Inline Model Numbers (NPTF)

Accessories

Remote Pilot Regulators

Any ROSS Controls standard or precision regulator providing adequate output pressure range can serve as the pilot supply for the series. For the extended high-capacity 4000 scfm configuration, a pilot regulator with accurate, stable output at the target working pressure is critical for precise regulation. ROSS 120 Series Miniature Precision Regulators are commonly used as remote pilot adjustment units.

Pressure Gauges

0 to 200 psig (0 to 14 bar) gauges for the 1/4" NPT gauge ports at the main body. At large-bore central supply installations, gauges at the regulator outlet provide continuous verification of commanded working pressure for operations monitoring.

Upstream High-Capacity Filters

ROSS Controls high-capacity inline filters for upstream 5-micron particulate protection of the series in large-bore central supply applications. Contact ROSS Controls for filter model selection matched to the series port size and flow requirement.

Related Products & Accessories

• 123 Series High-Capacity Precision Regulator - High-capacity inline precision regulator for 3/4" to 1-1/2" ports, flow to 800 scfm, with direct local set point adjustment. https://www.rosscontrols.com/en/series/123-high-capacity-precision-series
• 124 Series Full-Size Remote Pilot Regulator - Full-size modular remote pilot regulator for 1/4" to 3/4" ports, flow to 155 scfm. https://www.rosscontrols.com/en/series/124-full-size-series-remote-pilot-reg
• 125 Series MD4 Remote Pilot Regulator - MD4 modular remote pilot regulator for 3/8" to 3/4" ports, flow to 190 scfm. https://www.rosscontrols.com/en/series/125-md4-series-remote-pilot-reg
• 128 Series High-Flow Relief Valves - High-flow inline relief valves used in conjunction with remotely piloted fill regulators like the series. https://www.rosscontrols.com/en/series/128-high-flow-series
• ROSS High-Capacity Inline Filters - Large-bore inline filters for upstream particulate removal in high-flow Series applications. https://www.rosscontrols.com/en/categories/filters
• ROSS L-O-X Lockout Valves - Energy isolation lockout valves for installation upstream of Series high-capacity supply regulators for LOTO compliance. https://www.rosscontrols.com/en/categories/lockout-valves

Frequently Asked Questions (FAQ)

Q: What is the maximum flow capacity of the series?

A: The extended high-capacity 3" variant of the series provides flow up to 4000 scfm (113280 l/min). This is the highest flow capacity in the ROSS remote pilot regulator family and among the highest in the entire ROSS FRL product line. The standard 3/4"-1-1/2" inline variant reaches 740 scfm.

Q: When should I choose the high-relief variant over the standard inline variant?

A: Choose the high-relief variant when the inlet-to-outlet pressure differential is large. In standard regulators, large pressure drops can cause instability or hunting due to insufficient spring force to maintain stable valve positioning. The high-relief variant uses a higher-force spring that provides stable regulation across large pressure differential conditions. Contact ROSS Controls engineering if you are unsure which variant is appropriate.

Q: What is the difference between diaphragm and piston construction in the extended variants?

A: Diaphragm construction provides higher sensitivity to downstream pressure changes, resulting in tighter outlet pressure regulation and better response to rapid demand changes. Piston construction uses a piston with o-ring seals instead of a diaphragm; it is more tolerant of contaminated or lubricated air and has higher mechanical durability in pulsating flow conditions. For most compressed air applications, diaphragm is preferred. Piston is typically chosen when air quality is below recommended levels or when extreme mechanical durability is required.

Q: How far away can the pilot regulator be from the series main body?

A: Pilot regulators can be located tens of feet to hundreds of feet from the main body in large facility installations. Longer pilot lines have slightly slower response to pilot set point changes due to the larger pilot line volume, but for most non-dynamic applications this is acceptable. For very long pilot lines or applications requiring rapid set point tracking, consult ROSS Controls for pilot line sizing guidance.

Q: Can the series be used with electro-pneumatic transducers for automated pressure control?

A: Yes. I/P (current-to-pressure) or E/P (voltage-to-pressure) transducers can serve as the pilot source, enabling PLC, DCS, or SCADA systems to command downstream pressure digitally or proportionally. This configuration is used extensively in automated facility air supply management systems.

Q: What is the inlet pressure rating?

A: Standard and high-relief variants accept inlet pressures up to 300 psig (21 bar). The premium high-relief variant extends this to 400 psig (28 bar). Extended large-bore and high-capacity variants use 300 psig maximum inlet. Verify the specific variant's rating for the application before installation.

Q: What seal options are available?

A: Nitrile (Buna-N) seals are standard across all Series variants. Fluoroelastomer seals are available in the 3" extended high-capacity configuration (model 5X00B9021) for chemical resistance to hydrocarbons, solvents, and other substances incompatible with Nitrile.

Q: Is the series self-relieving?

A: Yes. All standard Series configurations are self-relieving: downstream pressure vents through the main body when pilot set pressure is reduced. This prevents downstream pressure from exceeding the commanded set point when the pilot is turned down.

Q: What pipe thread standards are available at 3" port size?

A: The 3" extended high-capacity configuration is available in both NPTF (model 5211B9008 or 5X00B9021) and G (BSPP) thread (models with C prefix). Confirm the required thread standard for the specific large-bore piping system before ordering.

Q: What upstream filtration is required?

A: A minimum 5-micron upstream filter is recommended. At large port sizes and high flow rates, high-capacity inline filters matched to the series port size should be used. Contact ROSS Controls for filter selection matched to the specific Series port size and flow application.

Q: Can I use the series for gases other than compressed air?

A: The Series is rated for filtered compressed air service. Nitrogen, argon, and other inert dry gases may be compatible given the aluminum body, brass/aluminum valve components, and Nitrile or Fluoroelastomer seals - but this must be confirmed with ROSS Controls for each specific application, including system safety analysis.

Q: What is the 128 Series and how does it relate to the series?

A: The 128 Series High-Flow Relief Valve is often used in the same circuit as the series remote pilot regulator. In a common circuit, the series remotely piloted regulator fills a downstream volume, and the 128 Series relief valve exhausts when the fill pressure exceeds a set point (typically 2 psig above the regulated pressure). This combination provides both fill regulation and high-flow relief in large-volume pneumatic systems.

Installation & Maintenance Guidelines

• Select the correct Series variant for the required port size, flow capacity, and pressure differential. Consult ROSS Controls if the application parameters do not clearly map to a standard variant.
• Install the main body in the compressed air distribution system inline with the supply piping. Support the regulator body independently from the piping to prevent pipe load from bearing on the body connections.
• Route the 1/4" NPTF pilot signal line from the remote pilot regulator outlet to the main body pilot port. Use clean, dry 1/4" OD tubing with no kinks or sharp bends. Protect the pilot line from mechanical damage over long runs.
• Install a minimum 5-micron upstream filter. At high flow and large port sizes, verify the upstream filter has adequate flow capacity to avoid filter-induced pressure drop at peak demand.
• Ensure inlet supply pressure does not exceed the rated maximum for the specific variant: 300 psig (21 bar) standard, 400 psig (28 bar) for premium variants.
• Verify gauge ports are equipped: install 0-200 psig gauges at the main body front or rear 1/4" NPT ports for outlet pressure monitoring. Plug unused gauge ports.
• Maintain ambient temperature within 40 to 175 F (4 to 79 C) for standard Nitrile configurations. Confirm Fluoroelastomer configuration temperature limits with ROSS Controls for extended applications.
• For the 3" high-capacity extended configuration, ensure that the piping and support structure can handle the additional weight and forces from the larger body at 4000 scfm flow conditions.
• Commission the system by setting the pilot regulator to the minimum desired working pressure, verifying main body outlet at minimum, then increasing to maximum desired pressure and verifying tracking across the full range.
• In circuits combining the series with a 128 Series High-Flow Relief Valve, verify the relief valve set point is at least 2 psig (0.1 bar) above the series regulated pressure to prevent nuisance relief operation at the required working pressure.

Warranty & Global Support

ROSS Controls provides a one-year warranty on all products, covering defects in material and workmanship from the date of purchase.

Technical and application engineering support for the series central supply and large-volume remote pilot applications is available through ROSS Controls USA at (800) 438-7677.

Global technical support through ROSS Controls offices in Canada, Brazil, Germany, France, United Kingdom, India, China, and Japan.

Visit rosscontrols.com for Series variant selection guides, dimensional data, flow performance curves, and authorized distributor information.

Download Catalog: https://www.rosscontrols.com/en/documents