R900941174 DBW10A1-5X/200-6EG24N9K4 German Rexroth electromagnetic overflow valve

Frequently Asked Questions (FAQ)

Q1: What is the difference between DB10 and DBW10?

DB is a pilot relief valve only — it limits pressure. DBW adds an integrated directional solenoid valve on top: when the solenoid is energized the main stage is unloaded (system goes to tank at near 0 bar), when de-energized it functions as a normal relief valve at the set pressure.

Q2: What does "A1" mean vs "B1/B2"?

"A" = version for subplate mounting (NG10). "1" = adjustment type = hexagon socket with protective cap (Allen key). B1/B2 denote alternative performance characteristics or adjustment styles — functionally the same relief range but different trim curves. This unit is the A1 (cap-adjustable) version.

Q3: How do I adjust the relief pressure?

With the system off/depressurized, remove the protective cap, turn the setscrew with an Allen key — clockwise = increase, counterclockwise = decrease. Factory preset is typically near minimum of the spring range. Reinstall cap and verify with a gauge. The solenoid does NOT change the set pressure — it only enables/unloads the valve.

Q4: How does the solenoid function — normally open or closed?

Standard logic: Solenoid DE-energized = relief active​ at set pressure. Solenoid ENERGIZED = main valve unloaded​ → P connects to T, system pressure drops near tank pressure (unloading function). Verify your application's required logic before wiring.

Q5: Which subplate and electrical plug are needed?

• Subplate: standard NG10 (ISO 6264)​ with P and T ports (G 1/2" or M18×1.5 on subplate), four M10 bolts @ ~35–40 N·m.

• Electrical: EN 175301-803 Form A (DIN 43650-A) 3-pin + PE connector (K4 type mating plug), 24 V DC. Polarity does not matter for DC solenoid, but indicator LED in the plug does — observe (+) / (–) markings on the plug if it has an LED.

Q6: Common faults & causes?

• Solenoid clicks but no unloading / system stays pressurized:​ pilot orifice clogged, main spool stuck, incorrect wiring (no current to coil — check with multimeter ~18–28 Ω typical), manual override not fully released.

• Pressure won't reach set value / creeps early:​ pilot damping hole blocked, contaminated pilot seat, wrong spring (/200 mis-ordered as lower range), excessive T-backpressure (internal pilot drain).

• Coil gets hot / burnt smell:​ overvoltage (>10% above 24V), wrong voltage class plugged in, or coil mechanically damaged — replace coil only with correct G24 type.

• Chatter / instability:​ air in system, very high T-backpressure, or worn pilot seat — bleed air first.

Q7: Can T-port backpressure affect the set pressure?

Yes — this model has internal pilot drain. Backpressure at T adds 1:1 to the relief setpoint. If your T-line has >5 bar sustained backpressure, consider the DBW…Y version (external pilot drain to separate tank line).

Q8: Fluid & seal notes?

NBR seals = mineral oil (HL/HLP) & HFC (water-glycol). For HEES/HETG biodegradable or HFD phosphate ester → specify FKM (Viton) seal variant. Maintain oil cleanliness per ISO 4406 code 18/16/13 or better.