DB20K1-1X/350Y DB20-1-5X/315 DB20-2-5X/100 Rexroth Pressure Relief Valve 350 bar

Product Overview

The DB series pilot-operated pressure relief valves are engineered by Bosch Rexroth for reliable system pressure limitation in industrial hydraulic applications. Featuring a two-stage design combining a pilot control valve with a main spool, these valves precisely limit operating pressure and provide overpressure protection for hydraulic systems.

The DB series covers nominal sizes from NG10 to NG32, supporting both subplate mounting (ISO 6264 porting patterns) and screw-in cartridge configurations. Valve bodies are manufactured from GGG40 (ductile cast iron) with phosphate coating for enhanced corrosion resistance and structural strength.

Our complete range of Rexroth DB pressure relief valves strictly adheres to OEM technical standards, achieving 100% direct interchangeability with original components. Every unit undergoes 100% simulated operating condition bench testing prior to shipment, ensuring performance parameters are fully consistent with genuine Rexroth products. Direct replacement of same-model Rexroth valves significantly reduces equipment downtime and maintenance costs.

⚠️ Model Code Decoding:

• DB = Pilot-operated pressure relief valve

• 20 = Nominal size NG20

• K1 / 1 / 2 = Adjustment type (K1 = hexagon sleeve with protective cap; 1 = lockable rotary knob with scale; 2 = hexagon adjustment screw)

• 1X / 5X = Component series

• /350Y / /315 / /100 = Set pressure (bar) and pilot oil drain (Y = external drain)

• DB10-1-52315 is an earlier/alternative coding format corresponding to DB10-1-5X/315

Technical Specifications 

DB20K1-1X/350Y (R900412192)

• Product Series: Bosch Rexroth DB series pilot-operated pressure relief valve

• Model Code: DB20K1-1X/350Y

• Material Number (MPN): R900412192

• Nominal Size: NG20 (Size 20)

• Component Series: 1X

• Maximum Operating Pressure: 350 bar (5000 psi)

• Maximum Flow Rate: 400 L/min (106 gpm)

• Adjustment Type: Hexagon sleeve with protective cap

• Sealing Material: FKM (Fluorocarbon rubber)

• Pilot Oil Drain: External (Y version)

• Mounting Type: Screw-in cartridge valve (M28×1.5 cavity)

• Number of Ports: 3

• Compatible Hydraulic Fluids: HL, HLP, HLPD, HVLP, HVLPD, HETG, HEES, HEPG, HFDU, HFDR

• Weight: Approx. 0.36 kg

DB20-1-5X/315 (R900587346)

• Product Series: Bosch Rexroth DB series pilot-operated pressure relief valve

• Model Code: DB20-1-5X/315

• Material Number (MPN): R900587346

• Nominal Size: NG20 (Size 20)

• Component Series: 5X

• Maximum Operating Pressure: 350 bar

• Set Pressure Range: Up to 315 bar

• Maximum Flow Rate: 650 L/min (configuration dependent)

• Adjustment Type: Lockable rotary knob with scale

• Sealing Material: NBR (Nitrile rubber)

• Mounting Type: Subplate mounting

• Porting Pattern Standard: ISO 6264

• Compatible Hydraulic Fluids: HL, HLP, HLPD, HVLP, HVLPD, HFC

• Weight: 2.6 – 4.4 kg (configuration dependent)

DB20-2-5X/100 (R900589433)

• Product Series: Bosch Rexroth DB series pilot-operated pressure relief valve

• Model Code: DB20-2-5X/100

• Material Number (MPN): R900589433

• Nominal Size: NG25 (Size 25)

• Component Series: 5X

• Maximum Operating Pressure: 350 bar

• Set Pressure Range: Up to 100 bar

• Maximum Flow Rate: 400 – 650 L/min (configuration dependent)

• Adjustment Type: Hexagon adjustment screw

• Sealing Material: NBR (Nitrile rubber)

• Mounting Type: Subplate mounting

• Porting Pattern Standard: ISO 6264 (NG25)

• Compatible Hydraulic Fluids: HL, HLP, HLPD, HVLP, HVLPD, HFC

• Weight: Approx. 3.88 kg

DB10-1-52315 (corresponds to DB10-1-5X/315)

• Product Series: Bosch Rexroth DB series pilot-operated pressure relief valve

• Nominal Size: NG10 (Size 10)

• Component Series: 5X

• Maximum Operating Pressure: 350 bar

• Set Pressure Range: Up to 315 bar

• Maximum Flow Rate: 250 L/min

• Mounting Type: Subplate mounting

Key Technical Advantages

1. Pilot-Operated Two-Stage Control for High-Precision Pressure Limiting
The DB series employs a two-stage design combining a pilot control valve with a main spool. System pressure is set via the pilot valve, with the main valve precisely opening for relief when the set pressure is reached. Compared to direct-acting relief valves, the pilot-operated design delivers superior pressure regulation accuracy and stability under high-pressure, high-flow conditions.

2. High Pressure Rating and Extensive Flow Capacity
The full series supports maximum operating pressures up to 350 bar, with flow capacities ranging from 250 L/min (NG10) to 650 L/min (NG32). Screw-in cartridge versions (DB20K1-1X/350Y) deliver 400 L/min flow in a compact package, while subplate-mounted versions achieve up to 650 L/min.

3. Flexible Pilot Oil Circuit Configurations and Multiple Adjustment Options
Supports multiple pilot oil supply and drain configurations including internal/external pilot supply and internal/external drain. The Y version (external drain) prevents back pressure in the pilot drain line from affecting set pressure accuracy. Adjustment options include hexagon sleeve with protective cap, lockable rotary knob with scale, and hexagon adjustment screw—accommodating diverse operational requirements.

4. Superior Seal Compatibility and Corrosion Protection
Sealing materials available in NBR and FKM options, compatible with HL, HLP, HLPD, HVLP, HVLPD, HFC, HETG, HEES, HEPG, HFDU, HFDR hydraulic fluids. Valve bodies are manufactured from GGG40 ductile cast iron with phosphate surface coating, providing excellent corrosion resistance and structural strength.

5. 100% Direct Interchangeability and Simulated Condition Testing
All models strictly adhere to Rexroth original mounting dimensions and interface standards, enabling direct drop-in replacement of original valves without piping modification or system adjustment. Every unit undergoes 100% simulated operating condition bench testing prior to shipment, ensuring consistent, stable performance at rated pressure and flow.

Application Areas

• Industrial Hydraulic Systems: Pressure limitation and overpressure protection for hydraulic power units and stations

• Construction & Earthmoving Machinery: Excavators, wheel loaders, cranes

• Injection Molding & Die-Casting: Hydraulic system pressure control and safety protection

• Metallurgical Equipment: Rolling mills, continuous casting equipment, lifting platforms

• Marine & Offshore: Steering gear, windlass, hatch cover hydraulic systems

• Wind Power: Hydraulic pitch control systems, brake system pressure protection

Expert Maintenance Tips

1. Verify Model Compatibility Prior to Installation
Confirm that the valve model matches system requirements—pay special attention to: nominal size (NG10/NG20/NG25/NG32), set pressure range, mounting type (ISO 6264 subplate porting pattern or cartridge cavity dimensions), and pilot oil circuit configuration (internal/external supply and drain).

2. Mounting Surface Cleanliness and Sealing
Ensure the mounting surface is clean and free of debris before subplate installation. Replace O-ring seals with new components and install correctly. Use a torque wrench to tighten mounting bolts diagonally to the torque values specified in Rexroth technical manuals to prevent valve body distortion or leakage.

3. System Cleanliness Management
Hydraulic system contamination is the leading cause of relief valve malfunction. Thoroughly flush system piping prior to installation. Recommended system cleanliness: ISO 4406 standard 18/16/13 or higher. For screw-in cartridge versions (e.g., DB20K1-1X/350Y), confirm the cavity is clean and free of burrs before installation.

4. Pressure Setting and Commissioning
Factory set pressure is nominal—recalibrate on-site according to actual system requirements. During commissioning, start from low pressure and gradually increase to the set value while monitoring pressure gauge response for smooth operation. DB series valves can be unloaded or switched to a secondary pressure setting via port X.

5. Periodic Maintenance and Inspection
Perform functional checks every 2,000 operating hours or annually, including: set pressure verification, leakage inspection (P→T ports), and response characteristic testing. If abnormal pressure fluctuation, sluggish response, or set pressure drift is observed, arrange for servicing or replacement.