Valves Installation and Service User Manual

General Precautions and Safety Information

Automatic Valve products are general-purpose industrial pneumatic and vacuum devices. While not inherently harmful, the control systems in which they operate must have necessary safeguards to prevent injury or damage should component failure occur. Products must only be used within the operating specifications stated in each catalog section or on the drawings. Power presses require special dual safety clutch and brake valves per OSHA Regulation 1910.217 and ANSI Standard B11.1, which Automatic Valve does not manufacture. The manual provides important information on two-position and three-position valve behaviors, including closed center, open center, and power center configurations, as well as solenoid manual override precautions.

Valve Sizing Calculations and Selection Charts

The manual includes detailed valve sizing information to help engineers and technicians select the correct valve for their application. The primary sizing method uses the Cv (flow coefficient) formula, which accounts for temperature, pressure, pressure drop, and flow rate to calculate the required valve capacity.

Cv Calculation Method

The Cv formula requires three steps: First, determine the cylinder operating speed (S) in feet per minute using the stroke length and extension/retraction time. Second, determine the volume of free air (Q) in standard cubic feet per minute using the cylinder diameter, operating speed, and inlet pressure. Third, apply these values to the Cv formula. The manual provides a worked example: a 2-inch bore by 2-inch stroke cylinder extending in 0.5 seconds at 80 psig inlet pressure with a 10 psi pressure drop requires a Cv of approximately 0.094.

Valve Sizing Chart and Quick Reference

For quick approximations, the manual includes a Valve Sizing Chart that assumes 80 PSIG inlet pressure, a 10% pressure drop, no line restrictions, and a valve-to-cylinder distance of 6 feet or less. The chart spans cylinder bore sizes from 0.75 inches to 12 inches and Cv values from 0.1 to 32.0, allowing technicians to look up the required Cv based on cylinder speed in inches per second. A separate SCFM-to-Cv approximation table provides conversion factors for inlet pressures from 30 to 120 PSIG.

Valve Conversion Chart

The Valve Conversion Chart shows how single operator spring return valves with balanced spools can be configured for different operating modes by plugging specific ports. Configurations include 2-way normally closed, 2-way normally open, 3-way normally closed, 3-way normally open, 3-way diverter, 3-way selector, and 4-way operation. The chart identifies which ports to plug, which to use for supply, outlet, and exhaust for each configuration. Minimum operating pressure is 35 psi, and an external pilot is required when using a port other than Port 1 for supply or when using a fluid media besides air.

Installation Guidelines for Automatic Valve Products

The installation section provides comprehensive guidance for properly installing Automatic Valve pneumatic products. Installation must be performed by trained and qualified personnel who understand how specific pneumatic products are to be piped and electrically connected. Products should only be installed in systems that contain adequate safeguards to prevent injury or damage in the event of product failure.

Operating Media, Air Lines, and Pipe Preparation

Automatic Valve products are designed primarily for use with air or other inert gases. For other media, contact your distributor. When solenoid piloted valves are used for vacuum service, an external pilot supply must be used. Before installing any pneumatic product, air lines should be blown clean to remove all contamination, and line filters should be cleaned after purging.

Automatic Valve recommends pipe sealant instead of Teflon tape when making connections to NPT ports. Sealant should be applied behind the first two or three threads to prevent contamination of the system. A general rule for NPT fittings is to install hand tight and then turn an additional 1 to 1.5 turns.

Mounting, Inlet Lines, Outlet Lines, and Exhaust Ports

Spool valves must be mounted with the spool in a horizontal position. Other valves, cylinders, and accessories may be mounted in any position. Mount valves so they are accessible for service and so that solenoid manual overrides can be used if applicable.

Valve inlet lines should have an inside diameter equal to or greater than the valve's inlet port size. The manual provides an inlet line sizing chart from 1/8 NPT (0.25-inch minimum ID) through 1-1/2 NPT (1.50-inch minimum ID). Restricted inlet lines reduce system operating speed and can cause valve malfunction. Locate valves as close as possible to the devices they operate and minimize sharp bends.

Spool valve exhaust ports may be restricted to provide cylinder speed control. Poppet valve exhaust ports must not be restricted, as restriction causes valve malfunction. All open exhaust ports should have mufflers installed to reduce noise and prevent atmospheric contamination.

Filtration, Operating Pressures, Pilot Pressure, and Lubrication

Filters with 50-micron elements are adequate for all Automatic Valve products, and should be installed within 20 feet of the valve. Operating pressures and temperatures must be within the minimum and maximum limits specified in each catalog section. Pilot pressure must also be within specified limits; for operation outside these ranges, an external pilot supply (option B) must be used.

Automatic Valve products are pre-lubricated at the factory. Additional lubrication is not required but is recommended. Compatible oils are paraffinic, petroleum-based with oxidation inhibitors, ISO 32 or lighter viscosity, and an aniline point between 82°C (180°F) and 99°C (210°F). Lubricators should be installed downstream of regulators. Lubricants should not be synthetic, reconstituted, or contain alcohol or detergent additives.

Maintenance and Preventative Care

The maintenance section establishes best practices for keeping Automatic Valve products operating reliably. Only qualified personnel who understand the function and operation of the product should perform service. Before servicing any pneumatic system, verify that air and electrical power are off and all system air is exhausted.

Preventative maintenance includes: proper installation per the Installation section, periodic draining, cleaning and servicing of air line filters, adjusting lubricators to approximately one drop per minute and filling reservoirs on schedule, keeping electrical switches and relay contacts in good condition, inspecting mechanical actuators for wear, and establishing periodic cleaning programs for extreme operating conditions. To clean products, use a water-soluble detergent — never use abrasive compounds or scrape metal parts.

When servicing, use only components from Automatic Valve service kits. After disassembly, discard all designated service kit items. Clean metallic components (except solenoid coils and housings) with non-abrasive, water-soluble detergent. Lubricate designated items during reassembly and test per drawing instructions.

Troubleshooting Guide with 17 Solutions

The most extensive section of the manual is the troubleshooting guide, which addresses 11 common valve problems with cross-references to 17 detailed solutions. The troubleshooting table format helps technicians quickly identify possible causes for each symptom and jump to the relevant solution.

Common Valve Problems Covered

The troubleshooting guide addresses: (1) Valve leaks to exhaust when not actuated, (2) Valve leaks to exhaust when actuated, (3) Solenoid pilot leaks, (4) Operator vent leaks, (5) Sluggish operation, (6) Poppet valve chatter, (7) Solenoid buzzes or solenoid burnout, (8) Solenoid valve fails to shift electronically but shifts with manual override, (9) Solenoid valve fails to shift electronically or with manual override, (10) Valve shifts but fails to return, and (11) Cam operated valve fails to operate. Each problem links to one or more detailed solution procedures.

Detailed Solutions for Valve Issues

The 17 solutions cover the full spectrum of pneumatic valve issues: (1) Valve exhaust port leakage diagnostics to determine whether leakage originates from the cylinder or valve, (2) Inadequate air supply troubleshooting, (3) Pilot supply verification, (4) Liquid contamination remediation, (5) Solid contaminant removal, (6) Solenoid pilot leakage repair, (7) Operator vent leak repair, (8) Muffler sizing and cleaning, (9) Improper lubrication correction, (10) Incorrect solenoid voltage diagnosis, (11) Faulty or dirty solenoid cleaning and replacement, (12) Manual override left activated, (13) Defective coil or wiring diagnostics, (14) Broken spring replacement, (15) Mechanical binding diagnosis, (16) Cam or roller adjustment, and (17) General maintenance procedures.

Glossary and Pneumatic Symbols Reference

The manual includes a comprehensive glossary of pneumatic terminology covering key terms such as ambient temperature, ATEX, CE certification, Celsius, CSA, Cv (flow coefficient), detent, DIN EN 175301-803, Fahrenheit, fluid, FM, kPa, media, media temperature, NEMA 4, NEMA 7, pressure range, psi, psia, psig, PTB, scfm, signal, standard air, and vacuum.

The pneumatic symbols section provides visual references for: 2-way, 3-way, 4-way, and 5-way valves in 2-position and 3-position configurations (closed center, exhaust center, pressure center), valve operators (spring, manual, push button, lever, pedal, mechanical, detent, solenoid, pilot pressure), accessories (flow control valve, check valve, exhaust restrictor, shuttle valve, muffler), and miscellaneous symbols (lines crossing, lines joining, direction of air flow, filters, regulators, lubricators, compressors, pressure switches, and cylinders).

Warranty and Safety Warnings

The cautions, warnings, and standard warranty section reiterates critical safety information: all energy sources must be locked out before service per OSHA 1910.147, only qualified personnel should service products, and all products must be functionally tested before reinstallation. The ROSS Group standard warranty provides one-year coverage from date of purchase (seven years for FRLs) for defects in material and workmanship, with the usual exclusions for misuse, misapplication, or improper maintenance.

Frequently Asked Questions

How do I calculate the correct Cv to size an Automatic Valve pneumatic valve?

To calculate the required Cv, use the three-step process in the manual: (1) Calculate the cylinder operating speed from the stroke length and desired time, (2) Calculate the volume of free air (Q) using the cylinder diameter, speed, and inlet pressure, and (3) Apply these values to the Cv formula. Alternatively, use the Valve Sizing Chart for a quick approximation at 80 PSIG with a 10% pressure drop, or the SCFM-to-Cv conversion table for other inlet pressures.

Can spool valve exhaust ports be restricted, and what about poppet valves?

Spool valve exhaust ports may be restricted to provide cylinder speed control — this is a common and acceptable practice. However, poppet valve exhaust ports must never be restricted, as restriction causes valve malfunction or oscillation. For cylinder speed control with poppet valves, use external flow control valves instead. All open exhaust ports should have mufflers installed to reduce noise and prevent contamination.

What should I do if my Automatic Valve solenoid is buzzing?

Solenoid buzzing can be caused by incorrect voltage, broken or damaged shading rings, or dirt on the plunger or around the top seat. First, verify that the operating voltage is within 90-110% of the rated voltage shown on the coil. If voltage is correct, shut off electrical power and disassemble the pilot section for inspection. Check the copper shading ring around the top seat and inspect the plunger guide for dirt or damage. Clean or replace components as needed.

What type of pipe sealant does Automatic Valve recommend for NPT connections?

Automatic Valve recommends pipe sealant rather than Teflon tape for NPT port connections. Apply the sealant behind the first two or three threads to prevent sealant from entering and contaminating the pneumatic system. No specific torque values are available for NPT fittings; the general rule is to install hand tight and then turn an additional 1 to 1.5 turns.

How often should I service air line filters and lubricators?

Air line filters should be drained, cleaned, and serviced on a periodic basis or as recommended by the manufacturer. Lubricator reservoirs should be filled on a scheduled basis with the proper lubricating oil at a flow rate of approximately one drop per minute. In extreme operating conditions, more frequent filter maintenance and a periodic internal cleaning program for valve components should be established.