Sun Hydraulics Pilot-to-Open Check Cartridge Valves

Reliable Load Holding | Controlled Reverse Flow | High-Pressure Performance

Sun Hydraulics’ Pilot-to-Open Check Valves are designed to allow free flow in one direction while preventing reverse flow until a specified pilot pressure is applied. These valves are essential for hydraulic circuits that require load holding, safety locking, or sequenced actuator movement.

Built with Sun’s signature screw-in cartridge design, these valves offer compact integration, high flow efficiency, and exceptional durability. When pilot pressure is introduced, the valve opens to allow reverse flow—enabling precise and safe control of actuators or loads under pressure.

Key Features:

🔁 Free Flow / Controlled Return: Allows flow in one direction; blocks reverse flow until pilot pressure is applied

🔧 Positive Load Holding: Prevents unintended actuator movement or load drop

📏 Adjustable Pilot Ratios: Available in a range of pilot-to-crack pressure ratios (e.g., 3:1, 4:1, 10:1)

💧 High Flow Capacity: Low pressure drop with excellent response characteristics

🧩 Standard ISO Cavities: Easy to install in manifolds or custom blocks

🛠️ Rugged Construction: Hardened components ensure long life and resistance to wear

Applications:

Hydraulic cylinder locking and load holding

Mobile equipment booms and arms

Industrial presses and material handling systems

Marine winches and davit cranes

Safety-critical actuating systems in offshore and oil & gas

Available Types:

Ball-style and poppet-style designs

Various pilot ratios (3:1 to 10:1)

Inline and manifold mounting options

Optional tamper-resistant designs