35 Series SERPAR® Double Valves Installation Instructions — Press Clutch/Brake Control

Overview

The ROSS Controls 35 Series SERPAR® Double Valves are a family of proven press safety pneumatic double valves designed to provide added safety in pneumatically controlled machines, with particular compliance for OSHA standards governing air clutch/brake mechanisms on mechanical power presses. The SERPAR® name — representing Series Parallel monitoring architecture — reflects the fundamental design principle of the 35 Series.

Available in Basic Sizes 4, 8, 12, and 30 with multiple monitor type options (E-P, L-G, D-S), the 35 Series SERPAR® Double Valve accommodates the full range of mechanical power press installations. Valves without monitors must be connected to an external monitoring system; valves with E-P, L-G, or D-S monitors include integral monitoring capability. Service kits are available for all valve body and monitor configurations.

ROSS Controls has manufactured press safety valves for over 100 years since 1921, pioneering the SERPAR® concept that continues to protect workers on mechanical power presses worldwide. Additional technical documentation and service kits are available at www.rosscontrols.com.

Key Features

OSHA-Compliant Press Clutch/Brake Control

When properly installed, the 35 Series SERPAR® Double Valve conforms to OSHA standards for the control of air clutch/brake mechanisms on certain mechanical power presses per 29 CFR 1910.217. The valve is designed to detect malfunctions in the valve's main elements and lock out the press if either element fails to operate synchronously, preventing hazardous press operation.

Multiple Monitor Options: E-P, L-G, D-S

The 35 Series is available with three integral monitor types: L-G (pneumatic lockout-gate monitor with manual or pneumatic reset), E-P (electro-pneumatic monitor with electrical reset), and D-S (electro-pneumatic differential switch monitor). Basic Size 4 valves with L-G monitors also offer a manual reset button option. Valves without monitors require connection to an approved external monitoring system.

Positive Lockout on Malfunction Detection

When the main valve elements do not both open or close at the same time, the integral monitor detects the discordance and locks the valve out — preventing the press from completing or initiating another stroke. The valve cannot be operated again until the monitor is reset. This positive lockout behavior is a fundamental safety requirement for mechanical power press operation under OSHA 1910.217.

Technical Specifications

Application: Press clutch/brake control — OSHA 29 CFR 1910.217 compliant (when properly installed)
Basic Sizes Available: 4, 8, 12, 30
Monitor Types: L-G (pneumatic reset); E-P (electrical reset); D-S (electro-pneumatic); none (external monitor required)
L-G Reset Pressure: Basic Size 4: minimum 30 psig (2 bar); larger sizes: minimum 60 psig (4 bar)
E-P Reset: Electrical signal to terminals 8 and 9 (reset solenoid) — momentary only
D-S Reset: External switch at terminals G and H — momentary close; or momentary power interruption
Reset Warning: Both solenoids must be de-energized before resetting any monitor
Electrical Supply: Basic Size 4 — plug-in connectors; larger sizes — internal terminal strip
Flow Media: Filtered compressed air (5-micron recommended)
Inlet Pressure: 30 to 125 psig (2 to 8.5 bar) — see specifications for specific size ranges
Compatible Lubricants: Petroleum base oils, aniline point 180°F–220°F, ISO 32 or lighter
Service Kits: Available for all sizes and monitor types (see service kit table in instructions)

Applications

Mechanical Power Press Operations

The 35 Series SERPAR® is the industry-standard double valve for mechanical power press clutch/brake control. It is used on single-stroke, partial-revolution, and full-revolution mechanical presses in metal stamping, blanking, punching, and forming operations. The OSHA 29 CFR 1910.217 compliance requirement for press safety controls has made the 35 Series SERPAR® a standard specification on new and retrofitted presses for decades.

Monitored Double Valve Applications

Beyond press clutch/brake control, the 35 Series SERPAR® can be used in other applications requiring a monitored double valve with positive lockout on discordance detection. The external monitor option allows integration with a variety of monitoring system architectures for non-press applications.

Safety and Compliance Standards

OSHA 29 CFR 1910.217 — Mechanical power presses (when properly installed with appropriate monitor)
ANSI B11.1 — Safety requirements for mechanical power presses
E-P Monitor: Dual input device — connect inputs only to terminals 1, 3, & 5
Reset Warning: Both solenoids must be de-energized before resetting — otherwise press can cycle immediately
External monitoring required for valves without integral monitors

Installation and Setup Guide

Air Line and Pilot Supply

Install a 5-micron air filter in the inlet line. Ensure Port 1 supply line is of adequate size without restrictions. Do not restrict the exhaust port.

Electrical and Monitor Wiring

Basic Size 4 valves use plug-in connectors. Larger sizes use an internal terminal strip — connect per the circuit diagram supplied with the valve. For E-P monitors: connect inputs only to terminals 1, 3, and 5 (dual input device). For D-S monitors: connect external switch to terminals G and H. An L-G lockout signal port can be connected to a normally closed pressure switch for lockout indicator light.

Post-Installation Testing

After installation: energize both solenoids; depress one manual override; de-energize both solenoids — this should result in valve lockout and prevent operation. Reset the monitor and repeat using the second manual override. After satisfying both tests, energizing both solenoids simultaneously should result in normal valve operation. Contact ROSS for testing procedures for valves without manual overrides.

Monitor Reset Procedures

L-G Monitor: Push manual reset button (Basic Size 4 with button) or apply air pressure to pneumatic reset port. E-P Monitor: Energize reset solenoid at terminals 8 and 9 — momentarily only (prolonged energization can burn out solenoid). D-S Monitor: Close external switch at terminals G and H momentarily, or momentarily interrupt power supply to the monitor.

Why Choose ROSS Controls

ROSS Controls invented the SERPAR® press safety valve technology and has been the trusted name in press safety for over 100 years. The 35 Series SERPAR® has protected press operators worldwide for decades and continues to be specified by press manufacturers, safety engineers, and plant maintenance professionals globally. Contact ROSS at 1-800-GET-ROSS or www.rosscontrols.com.

Download This Document

The official 35 Series SERPAR® Double Valves Installation Instructions (document SS094) provides complete specifications, wiring diagrams, monitor reset procedures, and service kit tables for all sizes and monitor types.

Download PDF: https://ross-admin-global-us-east.s3.amazonaws.com/production/uploads/document_language_file/file/37/ROSS_35_Series_SERPAR_Double_Valves_Installation_Instructions_SS094.pdf

Frequently Asked Questions

Q: What OSHA standard does the 35 Series SERPAR® valve comply with?

A: When properly installed, the 35 Series SERPAR® Double Valve conforms to OSHA 29 CFR 1910.217 standards for the control of air clutch/brake mechanisms on certain mechanical power presses.

Q: What monitor types are available for the 35 Series SERPAR®?

A: The 35 Series SERPAR® is available with L-G (pneumatic reset lockout-gate), E-P (electro-pneumatic with electrical reset), or D-S (differential switch) monitors, or without an integral monitor for use with an external monitoring system.

Q: What happens if I forget to de-energize solenoids before resetting the monitor?

A: WARNING: If either solenoid is energized when the monitor is reset, the press or machine can cycle immediately upon reset completion, creating a potentially fatal hazard. Always de-energize both solenoids before resetting any monitor.

Q: What reset pressure is required for the L-G monitor?

A: Basic Size 4 valves require at least 30 psig (2 bar) at the pneumatic reset port. All larger sizes require at least 60 psig (4 bar). Basic Size 4 models may also have a manual reset button option.

Q: How should the E-P monitor's reset solenoid be energized?

A: The E-P monitor reset solenoid should be energized only briefly (momentarily) at terminals 8 and 9. Prolonged energization can burn out the solenoid. The dual input terminals 1, 3, and 5 must be used for the dual input signals — not other terminals.

Q: Are service kits available for the 35 Series SERPAR®?

A: Yes. Service kits are available for valve bodies, gasket/seal kits, and all monitor types for all basic sizes. Refer to the service kit table in document SS094 for the correct kit part numbers for your valve size and monitor type.

Q: What inlet pressure range does the 35 Series SERPAR® support?

A: The 35 Series SERPAR® supports inlet pressures of 30 to 125 psig (2 to 8.5 bar). Consult the valve specifications in SS094 for exact pressure ratings for each basic size.

Q: What filter rating is recommended for the 35 Series SERPAR®?

A: A 5-micron rated air filter installed close to the valve inlet is recommended to prevent foreign material from causing valve malfunctions.