ROSS 31 Series and 36 Series Manual Valves — Installation and Operating Instructions

Overview

The ROSS® 31 Series and 36 Series Manual Valves are hand- or foot-operated poppet valves engineered for dependable pneumatic control in a wide range of industrial applications. Both series are built to ROSS's rigorous quality standards, offering long service life and tolerance of demanding operating environments.

The 31 Series provides 4/3 valve functionality with port sizes from 3/8 to 1-1/4 inch and bottom-ported connections, while the 36 Series covers 3/2 and 4/2 valve configurations with 1/4-inch ports and line-mount design. ROSS Controls, founded in 1921, brings over 100 years of fluid power expertise to these products.

This document covers installation procedures, valve maintenance, lubrication recommendations, technical specifications, service kit availability, and important safety warnings for both series. Always read and understand all instructions before beginning installation.

Key Features

31 Series 4/3 Valve Features

The 31 Series is a 4-port, 3-position valve with port sizes from 3/8 to 1-1/4 inch. All four ports are located on the bottom of the valve for clean sub-base mounting. Operators are horizontal or vertical lever. The center position can be configured with outlet ports open to exhaust (models ending in 07, 08, 09, or 12) or closed to exhaust (models ending in 10, 11, 13, or 14). Detented or non-detented operation is available.

Configuration: 4/3 (4-port, 3-position)
Port sizes: 3/8 to 1-1/4 inch
Operator: horizontal or vertical lever
Port location: bottom of valve
Center position options: open to exhaust or closed to exhaust
Detented or non-detented operation
Construction: Poppet
Mounting type: Bottom mounting flanges
Inlet pressure: 5 to 150 psig (0.3 to 10 bar)
Temperature: 40° to 175°F (4° to 80°C)

36 Series 3/2 and 4/2 Valve Features

The 36 Series is a compact line-mount poppet valve available in 3/2 and 4/2 configurations, both with 1/4-inch port sizes. Ports are located on the sides of the valve. Operators available include horizontal lever, vertical lever, pedal, and treadle. Both detented and spring-return operation are available.

3/2 configuration: port size 1/4 in, 3 ports on sides of valve
4/2 configuration: port size 1/4 in, 4 ports on sides of valve
Operators: horizontal lever, vertical lever, pedal, treadle
2-position control: detented or spring return
Mounting type: Line mounting
Inlet pressure: 5 to 125 psig (0.3 to 8.5 bar)
Temperature: 40° to 175°F (4° to 80°C)
Flow media: Filtered air; 5-micron filtration recommended
Construction: Poppet design

Service Kit Availability

Valve Body Service Kits contain all internal parts needed to recondition a valve body, including poppet and stem assemblies, springs and retainers, gaskets and seals. Locking Rocker Kits are available for detented-action models (model numbers ending in 07, 09, 10, or 13). Spring & Retainer Kits contain four poppet springs and retaining hardware.

Technical Specifications

31 Series Valve Specifications

Construction: Poppet
Mounting type: Bottom mounting flanges
Ambient/Media temperature: 40° to 175°F (4° to 80°C)
Flow media: Filtered air
Inlet pressure: 5 to 150 psig (0.3 to 10 bar)
Port sizes: 3/8 to 1-1/4 inch
Number of ports: 4 (located on bottom)
Positions: 3 (with detented or non-detented center)
Recommended filtration: 5-micron rated air filter

36 Series Valve Specifications

Construction: Poppet design
Mounting type: Line mounting
Ambient/Media temperature: 40° to 175°F (4° to 80°C)
Flow media: Filtered air; 5-micron filtration recommended
Inlet pressure: 5 to 125 psig (0.3 to 8.5 bar)
Port size: 1/4 inch
3/2 models: 3 ports on sides; 4/2 models: 4 ports on sides
Positions: 2 (detented or spring return)
Operators: horizontal lever, vertical lever, pedal, treadle

Applications

Press and Clamping Controls

The 31 Series 4/3 valve is widely used in hydraulic and pneumatic press controls, clamping cylinders, and reciprocating actuator applications where three distinct circuit positions — extend, retract, and center — are required. The detented models maintain position without continuous operator force.

Foot-Operated Valve Systems

The 36 Series with pedal or treadle operator is designed for applications where the operator requires both hands free. Machine tooling, welding fixtures, assembly jigs, and press brakes commonly use foot-operated 3/2 and 4/2 valves for safe and ergonomic cycle initiation.

Safety and Compliance Standards

Before servicing any valve or pneumatic component, all sources of energy must be turned off, the pneumatic system shut off and exhausted, and power sources locked out per OSHA 1910.147 and EN 1037. Only qualified persons trained in pneumatic equipment installation and maintenance should work on these products.

Use only ROSS parts to repair ROSS products. Do not restrict exhaust port air flow — this can adversely affect valve operation. ROSS silencers reduce impact noise by up to 25 dB while producing minimal back pressure. Exceeding the specified pressure and temperature limits can shorten valve life.

Installation and Setup Guide

Air Line Preparation

Before installing the valve in a new or existing system, blow air lines clean of all contaminants. Install an air filter close to the valve. Ensure the inlet line (Port 1) is of adequate size and free of crimps, sharp bends, or clogged elements. To reduce exhaust noise without increasing back pressure, install a ROSS silencer at the exhaust port (Port 3).

Pipe and Fitting Installation

To install pipe in valve or base ports: engage pipe one turn, apply pipe thread sealant (tape not recommended), then tighten pipe. This prevents sealant from entering the valve. For best response and control, locate the valve as close as possible to the actuated mechanism. All outlet lines must be of adequate size and free of crimps and sharp bends.

Lubrication and Cleaning

These valves do not require air line lubrication. If a lubricator is used for other mechanisms in the system, supply only oils specifically compounded for air line service — petroleum base oils with oxidation inhibitors, aniline point between 180°F (82°C) and 220°F (104°C), ISO 32 or lighter viscosity. Avoid oils with phosphate additives. To clean the valve, use a commercial solvent or kerosene; avoid chlorinated solvents and abrasives. Before reassembly, lubricate sliding surfaces with Mobil Grease 28 or equivalent.

Why Choose ROSS Controls

For over 100 years, ROSS Controls has designed and manufactured fluid power solutions trusted by industrial engineers worldwide. The 31 and 36 Series valves exemplify the ROSS commitment to poppet-valve reliability, compact design, and operator versatility. With global technical support and an extensive network of authorized distributors, ROSS provides the service support you need wherever you operate.

Contact ROSS Technical Services at 1-888-TEK-ROSS (835-7677) or call 1-800-GET-ROSS for installation and service assistance. Visit www.rosscontrols.com for the full product catalog and distributor locator.

Download This Document

The official PDF installation instructions for the ROSS 31 Series and 36 Series Manual Valves (Form SS104) are available for download:

PDF Download: https://ross-admin-global-us-east.s3.amazonaws.com/production/uploads/document_language_file/file/22/ROSS_31_36_Series_Manual_Valves_Installation_Instructions_SS104.pdf

Full document library: https://www.rosscontrols.com/en/documents

Frequently Asked Questions

Q: What are the port sizes for the 31 Series valve?

A: The 31 Series offers port sizes from 3/8 to 1-1/4 inch, with all four ports located on the bottom of the valve for sub-base mounting.

Q: What is the maximum inlet pressure for the 36 Series valve?

A: The 36 Series valve is rated for inlet pressures from 5 to 125 psig (0.3 to 8.5 bar). The 31 Series is rated for 5 to 150 psig (0.3 to 10 bar).

Q: Are the 31 and 36 Series valves available with detented action?

A: Yes. Both series are available in detented and non-detented configurations. Detented models maintain position without continuous operator input. Locking Rocker Kits are available for 31 Series models ending in 07, 09, 10, or 13.

Q: What center-position configurations are available for the 31 Series?

A: Models ending in 07, 08, 09, or 12 have outlet ports open to exhaust in the center position. Models ending in 10, 11, 13, or 14 have outlet ports closed to exhaust in the center position.

Q: Do these valves require air line lubrication?

A: No. These valves do not require air line lubrication. ROSS recommends a 5-micron rated filter in the circuit but no lubricator is needed for the valve itself.

Q: What operators are available for the 36 Series?

A: The 36 Series is available with horizontal lever, vertical lever, pedal, and treadle operators. All are available in detented or spring-return configurations.

Q: What solvent is safe to use when cleaning these valves?

A: Use any good commercial solvent or kerosene. Never use chlorinated solvents (which damage seals) or abrasive materials (which permanently damage metal parts). Lubricate all sliding surfaces with Mobil Grease 28 or equivalent before reassembly.

Q: What is the ROSS warranty period for these valves?

A: ROSS provides a one-year warranty from date of purchase for defects in material and workmanship. Products must be returned freight prepaid and confirmed defective for repair, replacement, or refund.