Product Overview
The DBW30A2-5X/315-6EW110N9K4 (Material Number R900918731) is a classic model in the Bosch Rexroth DBW series of pilot-operated solenoid relief valves, nominal size NG32 . The DBW series adds a solenoid directional valve to the DB series relief valve, enabling system pressure limiting and remote solenoid-actuated unloading . The valve consists of three main components: the main valve (with main spool insert), the pilot control valve (with pressure adjustment element), and the integrated directional spool valve .
The DBW30A2-5X/315-6EW110N9K4 features A spool symbol, 5X component series (50–59, unchanged installation and connection dimensions) , a maximum operating pressure of 350 bar, and a maximum flow rate of 650 L/min . This model is equipped with switching shock damping, which mitigates pressure peaks and acoustic decompression shocks in the return line by delaying the opening in channel B of the directional valve . Default nozzle diameter is Ø1.2 mm .
Model Code Breakdown (DBW30A2-5X/315-6EW110N9K4):
DBW: Pilot-operated pressure relief valve with solenoid unloading
30: Nominal Size NG32
A2: Spool symbol and configuration (A type)
5X: 5X Component Series (50–59)
315: Maximum pressure setting (315 bar)
6E: With directional spool valve
W110: Coil voltage — 110–120V AC (50/60Hz)
N9: With concealed manual override
K4: Without cable socket; device connector per DIN EN 175301-803
As an original Bosch Rexroth pilot-operated solenoid relief valve, this product offers complete interchangeability within the same series and size, requiring no modifications to mounting interfaces or piping layouts.
Technical Specifications
Model: DBW30A2-5X/315-6EW110N9K4
Material Number: R900918731
Brand: BOSCH REXROTH
Series: DBW Series, 5X Component Series
Product Type: Pilot-operated Solenoid Relief Valve
Spool Symbol: A type
Nominal Size: NG32 (G1 1/2″ threaded connection)
Mounting Standard: ISO 6264 (NG32)
Maximum Operating Pressure: 350 bar (5075 psi)
Maximum Flow Rate: 650 L/min
Pressure Setting Range: 315 bar (maximum)
Coil Voltage: 110–120V AC (50/60Hz)
Electrical Connector: Device connector per DIN EN 175301-803
Switching Shock Damping: Equipped (S)
Nozzle Diameter: Ø1.2 mm (R12)
Seal Material: NBR
Manual Override: Equipped (concealed)
Adjustment Type: Sleeve with hexagon and protective cap
Weight: Approx. 5.85 kg
Key Technical Advantages (DBW Series Common)
1. Pilot-Operated Design — High-Pressure High-Flow with Precise Control
The DBW30A2-5X/315-6EW110N9K4 features pilot-operated construction—the main valve is controlled by a pilot control valve, with the pilot spool controlling the main spool action . Compared to direct-acting relief valves, the pilot-operated design delivers superior pressure/flow stability, lower hysteresis, and more precise pressure control. Maximum operating pressure reaches 350 bar with flow capacity up to 650 L/min .
2. Integrated Solenoid Unloading — Remote Pressure Control
The DBW series adds a solenoid directional valve to the DB series relief valve, enabling remote solenoid-actuated system pressure unloading. When energized, the directional valve actuates, unloading system pressure to tank through the pilot valve . This allows the DBW valve to serve both as a system safety valve and a remote unloading valve.
3. Switching Shock Damping — Reduced System Noise and Shock
The DBW30A2-5X/315-6EW110N9K4 is equipped with switching shock damping . By delaying the opening in channel B of the directional valve, it effectively mitigates pressure peaks and acoustic decompression shocks in the return line . The damping level can be adjusted by selecting the appropriate nozzle size, with a default of Ø1.2 mm . This feature is particularly beneficial for reducing system noise and enhancing operational stability .
4. A Spool Symbol — Adapts to Specific System Requirements
The DBW30A2-5X/315-6EW110N9K4 features A spool symbol . The DBW series offers both A type and B type configurations, with A type adapting to specific hydraulic circuit design requirements.
5. 110–120V AC Supply — International Standard Voltage
This model operates on 110–120V AC (50/60Hz) supply , compatible with North American and select Asia-Pacific industrial power standards. IP65 protection effectively resists dust and water ingress.
6. International Standard Compliance for Global Interchangeability
Mounting conforms to ISO 6264 (NG32) international standards . The DBW series offers complete interchangeability with globally adopted NG32 size interfaces. The 5X component series ensures stable installation and connection dimensions .
Application Areas
Heavy-Duty Hydraulic Systems — Pressure control and unloading for rolling mills, forging equipment
Injection Molding Machinery — System pressure setting and unloading for large injection molding machines
Die-Casting Machines — Pressure control for high-pressure casting equipment
Large Hydraulic Power Units — Remote pressure unloading for high-flow hydraulic systems
Marine and Port Machinery — Pressure control for large winch and crane hydraulic systems
Expert Maintenance Tips
1. Installation Guidelines
DBW30A2-5X/315-6EW110N9K4 mounting must conform to ISO 6264 (NG32) standards .
Thoroughly clean the mounting surface and all ports (P, T) before installation to prevent foreign particles from entering and causing spool sticking or seal damage.
K4 suffix indicates without cable socket — users must separately select a compatible device connector per DIN EN 175301-803 .
2. Hydraulic Fluid Cleanliness
Compatible fluids: Mineral oils (HL, HLP, HLPD, HVLP, HVLPD, etc.) .
Seal material: NBR .
Recommended fluid cleanliness: ISO 4406 19/17/14 or better.
Install a return line filter with minimum 10 μm filtration rating.
3. Switching Shock Damping Adjustment
The DBW30A2-5X/315-6EW110N9K4 features switching shock damping .
The damping level can be adjusted by selecting the appropriate nozzle size .
Recommended nozzle diameter: Ø1.2 mm (R12) .
4. Electrical Connection Specifications
DBW30A2-5X/315-6EW110N9K4 uses 110–120V AC (50/60Hz) supply .
Electrical connector per DIN EN 175301-803 .
Ensure the connector is fully locked to maintain effective protection.
5. Pressure Setting Adjustment
DBW30A2-5X/315-6EW110N9K4 pressure setting range up to 315 bar .
Pressure adjustment is performed via the adjustment element on the pilot valve .
Adjust gradually under system operating conditions to achieve the desired pressure value.
6. Periodic Maintenance Inspection
Inspect the valve body for external oil leakage every 2,000 operating hours or at least annually.
Check electrical connectors for looseness, oxidation, or moisture ingress.
If pressure control instability or slow response is observed, first check system fluid cleanliness and verify the pilot spool is not sticking.
DBW series valves feature cast internal flow passages for excellent flow capacity and simple construction.
