R900926249 DBW10A2-5X/200-6EG24N9K4 Electromagnetic overflow valve from Rexroth, Germany

Frequently Asked Questions (FAQ)

Q1: What is the difference between DBW10A1 and DBW10A2?

Functionally identical. The only difference is the adjustment method:

• A1​ = hexagon socket setscrew (Allen key adjustable under cap).

• A2​ = rotary hand knob (turn by hand under cap, no tool needed).

  Both share the same pressure stages and flow ratings.

Q2: Is this direct-acting or pilot-operated?

It is a pilot-operated (two-stage) relief valve with solenoid unloading. The pilot stage controls the main spool for stable high-flow relief; the integrated solenoid can command the valve to unload the system to tank.

Q3: How do I adjust the relief pressure?

With system depressurized, lift/remove the protective cap and turn the rotary knob clockwise to increase, counterclockwise to decrease. Factory preset is typically near minimum of the spring range. Replace the cap after setting and verify with a pressure gauge. The solenoid does NOT change the set pressure.

Q4: What is the solenoid logic?

Standard: Solenoid DE-energized = relief active​ at set pressure. Solenoid ENERGIZED = system unloaded​ (P connected to T, near tank pressure). Confirm this matches your control logic before wiring.

Q5: Which subplate and electrical connector 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, 24 V DC. If the plug has LED indication, observe (+) / (–) polarity markings.

Q6: Common faults & causes?

• Solenoid clicks but system does NOT unload:​ pilot orifice clogged, main spool stuck, no coil current (check ~18–28 Ω), 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, or mechanical damage — replace only with correct G24 wet-pin coil.

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

Q7: Does T-port backpressure affect set pressure?

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).

Q8: Fluid & seal compatibility?

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.