R900941175 DBW20A1-5X/200-6EG24N9K4 Rexroth manufactures electromagnetic relief valves
Rexroth DBW series pilot-operated pressure relief valve with integrated solenoid unloading function. This electromagnetic relief valve provides pressure limiting at set value plus solenoid-actuated system unloading capability.
| Parameter | Value |
|---|---|
| Part Number | R900941175 |
| Model | DBW 20 - A1 - 5X / 200 - 6EG24N9K4 |
| Valve Type | Pilot-operated pressure relief valve with integrated solenoid unloading (DBW series) |
| Nominal Size (NG) | 20 - subplate mounting per ISO 6264 / NG20 |
| Function | Pressure limiting at set value + solenoid-actuated system unloading (energize → P→T open, system near 0 bar) |
| Adjustment Type | A1 = Hexagon socket setscrew with protective cap (Allen key adjustable) |
| Component Series | 5X (series 50-59, dimensionally interchangeable) |
| Max. Adjustable Relief Pressure | 200 bar (adjustment range typically 4-200 bar) |
| Max. Operating Pressure (P-port) | 350 bar |
| Max. Flow Rate (Qmax) | approx. 500 L/min (Size 20 DB/DBW series) |
| Pilot Oil | Internal pilot supply, internal pilot drain (standard DBW) |
| Solenoid Type | Wet-pin DC solenoid |
| Solenoid Voltage | 24 V DC (G24) |
| Electrical Connection | Plug-in socket per EN 175301-803 Form A (K4 = mating plug sold separately) |
| Manual Override | N9 = concealed push-button manual override on coil |
| Seal Material | NBR (standard, for mineral oil HL/HLP, HFC) |
| Hydraulic Fluid | Mineral oil HL, HLP per DIN 51524; HFC (water-glycol); HLPD, HVLP, HVLPD |
| Fluid Temperature Range | -30 °C to +80 °C (NBR seals) |
| Viscosity Range | 10-800 mm²/s |
| Weight (approx.) | 7.8 kg |
| Body Material | Cast iron / steel, zinc-plated |
DB is a pilot relief valve only - limits system pressure. DBW adds an integrated directional solenoid valve: when energized the main stage is unloaded (P→T open, near 0 bar); when de-energized it works as a normal relief valve at the set pressure. This is the DBW (unloading) version.
- A1 = subplate mounting (NG20), adjustment by hexagon socket with protective cap (Allen key)
- NG20 vs NG10: Size 20 handles higher flow (~500 L/min vs ~250 L/min), uses larger M12 mounting bolts, and requires an NG20 subplate (G 3/4" or M27×2 ports). Function, solenoid, and pressure stages are the same
With system depressurized, remove the protective cap, turn the setscrew with an Allen key - clockwise to increase, counterclockwise to decrease. Factory preset is typically near minimum of the spring range. Reinstall cap and verify with a pressure gauge. The solenoid does NOT change the set pressure.
Standard: Solenoid DE-energized = relief active at set pressure. Solenoid ENERGIZED = system unloaded (P connected to T). Confirm this matches your control logic before wiring.
- Subplate: standard NG20 (ISO 6264) with P and T ports (G 3/4" BSP or M27×2 on subplate), four M12 bolts @ ~70-80 N*m
- Electrical: EN 175301-803 Form A (DIN 43650-A) 3-pin + PE connector, 24 V DC. If the plug has LED indication, observe (+) / (-) polarity markings
- Solenoid clicks but system does NOT unload: pilot orifice clogged, main spool stuck, no coil current (check coil resistance), manual override jammed
- Pressure won't reach set value / creeps early: wrong spring (not /200), pilot damping hole blocked, contaminated pilot seat, excessive T-backpressure (internal pilot drain)
- Coil overheats / burnt smell: overvoltage (>10% above 24V), wrong voltage coil fitted - replace only with correct G24 wet-pin coil
- Chatter / unstable: air in system, high T-backpressure, worn pilot seat - bleed air first
Yes - this model has internal pilot drain. Backpressure at T adds 1:1 to the relief setpoint. If your tank line has >5 bar sustained backpressure, consider the DBW…Y version (external pilot drain to separate tank line).
NBR seals = mineral oil (HL/HLP) & HFC (water-glycol). For HEES/HETG biodegradable oils or HFD phosphate ester → specify FKM (Viton) seal variant. Maintain oil cleanliness per ISO 4406 code 18/16/13 or better.
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