Remote Pilot Piston Regulators MD4 Series Installation & Operating Instructions

Overview

ROSS Controls, founded in 1921 with over 100 years of leadership in fluid power, offers the MD4 Series Modular Remote Pilot Piston Regulators as a high-performance air pressure regulation solution designed for demanding industrial pneumatic systems requiring higher outlet pressure ranges. The MD4 Series delivers flows up to 170 scfm with an extended outlet pressure range of 0 to 250 psig (0 to 17 bar), making it suitable for higher-pressure applications where the Full-Size diaphragm series may not be applicable.

Like all ROSS remote pilot regulators, the MD4 Series uses pilot pressure — supplied by a separate remote control regulator — acting against the diaphragm to open and close the supply valve and maintain the set downstream pressure. The piston-assisted diaphragm design provides enhanced pressure stability at higher operating pressures. Overpressure is automatically relieved when pressure on the top of the diaphragm exceeds the pilot pressure acting on the bottom.

The MD4 Series is compatible with ROSS modular air preparation systems and accepts standard gauge ports on front and rear for pressure monitoring. For product support, contact ROSS at 1-800-GET-ROSS or visit www.rosscontrols.com.

Key Features

Extended High-Pressure Outlet Range

The MD4 Series offers an outlet pressure adjustment range of 0 to 250 psig (0 to 17 bar) — significantly higher than standard Full-Size models — making it the preferred choice for pneumatic systems supplying high-pressure tooling, hydraulic intensifiers, or other equipment requiring pressure above 125 psig. Inlet pressure is rated to 300 psig (21 bar) maximum.

High Flow Rate for Large-Volume Systems

With a rated flow of up to 170 scfm, the MD4 Series supports high-demand pneumatic circuits. The larger flow capacity makes the MD4 well-suited to plant-wide air distribution manifolds, multi-cylinder machine circuits, and other applications where high instantaneous air demand is a requirement.

Modular MD4 Platform Compatibility

The MD4 designation indicates compatibility with ROSS modular MD4 air preparation systems, allowing filter/regulators, lubricators, and other modules to be assembled on a common manifold using modular port brackets (part R-A118-105M) with a standard torque of 30-40 in-lbs. Port sizes of 3/8, 1/2, and 3/4 inch NPT are available, enabling the MD4 regulator to be matched to the system line size.

Technical Specifications

Construction: Diaphragm, self-relieving
Maximum Flow: 170 scfm
Ambient/Media Temperature: 40° to 175°F (4° to 80°C)
Fluid Media: Compressed air
Inlet Pressure: 300 psig (21 bar) maximum
Outlet Pressure: Adjustable 0 to 250 psig (0 to 17 bar)
Pilot Ports: 1/4 NPTF
Pressure Gauge: 0 to 200 psig (0 to 14 bar); 1/4 NPT gauge ports front and rear
Body and Dome: Zinc; Seals: Nitrile; Valve: Brass; Valve Cap: Nylon
Port Sizes: 3/8, 1/2, 3/4 inch NPT
Head Kit Part Numbers: R-KA116-01-3 (3/8), R-KA116-01-4M (1/2), R-KA116-01-6M (3/4)
Modular Port Bracket: R-A118-105M; Gauge port wall bracket: R-KA37-68; Extended bracket: R-KA37-68L

Applications

High-Pressure Pneumatic Tool Supply

The MD4 Series is ideal for supplying compressed air to high-pressure pneumatic tools, presses, and actuators requiring supply pressures above 125 psig. The extended outlet pressure range to 250 psig enables use with specialized pneumatic equipment that exceeds the capability of standard regulators.

Modular Air Preparation Systems

As part of the ROSS MD4 modular platform, this regulator integrates seamlessly with MD4 filters, lubricators, and integrated filter/regulators to create a complete, compact FRL assembly. This platform is especially popular in OEM machine design where a standardized, modular air preparation solution is needed across multiple machine configurations.

Safety and Compliance Standards

Pneumatic equipment installation and servicing must be performed by trained and experienced personnel. Before service, shut off the air supply, exhaust all system pressure, and lock out all power sources per OSHA 29 CFR 1910.147. Polycarbonate bowl caution: do not use with fluids other than compressed air. Avoid substances harmful to polycarbonate including acetone, benzene, solvents, and paints. Replace any polycarbonate bowl showing crazing or cracking immediately.

Installation and Setup Guide

Installation Steps

Step 1: Depressurize and lock out air pressure upstream of the regulator installation point.
Step 2: Install a 5-micron-rated filter immediately upstream of the regulator.
Step 3: Mount the MD4 regulator near the point of use, observing the flow direction arrow.
Step 4: Connect the 1/4 NPTF pilot supply line from the remote control regulator.
Step 5: Install pressure gauges or plugs in both front and rear gauge ports.
Step 6: If assembling in a modular system, use modular port bracket R-A118-105M, torque to 30-40 in-lbs.
Step 7: Apply pressure and adjust the remote pilot regulator to the desired outlet pressure.
Step 8: Lock out the pressure adjustment if tamper resistance is required.

Cleaning and Repair

Shut off the air supply and exhaust trapped air. Remove the supply valve by unscrewing the valve cap. Clean the valve seat with soap and water to remove accumulated dirt. The diaphragm requires pre-loading after assembly; dome removal is not recommended in the field. If the regulator cannot be repaired by cleaning and the pilot supply regulator is functioning properly, return the unit to ROSS for factory repair.

Why Choose ROSS Controls

ROSS Controls, founded in 1921 with over 100 years of leadership in fluid power, is the global leader in pneumatic safety and air preparation equipment. ROSS MD4 Series products are engineered for long service life, compatibility with the broader ROSS modular platform, and broad port size availability. Technical support is available at 1-800-GET-ROSS or www.rosscontrols.com.

Download This Document

The official PDF for the Remote Pilot Piston Regulators MD4 Series is available at: https://ross-admin-global-us-east.s3.amazonaws.com/production/uploads/document_language_file/file/197/ROSS_Regulator_Modular_Remote_Pilot_MD4_Series_SS-R016.pdf

Frequently Asked Questions

Q: What is the outlet pressure range of the MD4 Series?

A: Adjustable from 0 to 250 psig (0 to 17 bar), which is higher than the Full-Size Series maximum of 125 psig.

Q: What is the maximum inlet pressure?

A: 300 psig (21 bar) maximum inlet pressure.

Q: What flow rate does the MD4 support?

A: The MD4 Series is rated for flows up to 170 scfm.

Q: What pilot port size is used?

A: Pilot ports are 1/4 NPTF.

Q: Can the MD4 be used in a modular FRL assembly?

A: Yes. The MD4 Series is designed for the ROSS modular air preparation platform. Use modular port bracket R-A118-105M and torque connection screws to 30-40 in-lbs.

Q: What is the temperature range?

A: Ambient and media temperature range is 40° to 175°F (4° to 80°C).

Q: What materials are used?

A: Body and Dome: Zinc. Seals: Nitrile. Valve: Brass. Valve Cap: Nylon.

Q: How do I contact ROSS for service?

A: Call 1-800-GET-ROSS or visit www.rosscontrols.com to locate your nearest authorized ROSS distributor.