R900423720 DBDS6G1X/315 Rexroth Germany overflow valve

Frequently Asked Questions (FAQ)

Q1: Is DBDS6G1X/315 pilot-operated or direct-acting?

It is a direct-acting seat valve (DBD series). The ball/poppet opens immediately when system pressure overcomes the spring preload — no pilot stage is involved.

Q2: What does "G1X / 315" mean in the model?

• G​ = designed for threaded/screw-in cartridge installation into a manifold block with G 1/4" threaded cavity.

• 1X​ = component series index (dimensionally interchangeable within series 1X).

• /315​ = spring pressure stage — maximum adjustable relief pressure is 315 bar.

Q3: How do I install this valve?

The valve screws into a prepared manifold block cavity​ with G 1/4" ISO 228-1 threaded port. Ensure the P-port in the block aligns with system pressure and T-port connects to tank. Use appropriate sealing (O-ring on the cartridge shoulder or thread sealant on the threaded portion as per the cavity drawing). Torque typically approx. 45–50 N·m — refer to the official Rexroth mounting drawing for your specific cavity.

Q4: How do I adjust the relief pressure?

With the system depressurized, remove the protective cap, turn the internal setscrew with an Allen key — clockwise to increase, counterclockwise to decrease. Reinstall the cap after setting and verify with a pressure gauge at the P-port. Factory preset is typically near the low end of the spring range; always re-set on-site.

Q5: Does T-port backpressure affect the set pressure?

Yes. Backpressure at the tank side adds 1:1 to the cracking/relief pressure because the spring chamber drains internally to T. Keep T-line backpressure minimal or subtract it from your desired setpoint during adjustment.

Q6: What if the valve does not reach set pressure or chatters?

• Low/no pressure:​ Wrong spring grade, high T-backpressure, or severely contaminated oil causing poppet sticking.

• Chatter / noise:​ Air in the system, excessive flow beyond Qmax for Size 6, or remote piping resonance — bleed air from the system and confirm flow ≤50 L/min.

• Leakage in closed position:​ Damaged seating surface or contaminated oil trapped in the seat — clean or replace the cartridge.

Q7: Can it be used with biodegradable or water-based fluid?

Standard NBR seals are approved for HFC (water-glycol). For HEES/HETG biodegradable oils or HFD (phosphate ester), FKM (Viton) seals are required — order the "V" seal variant if needed and verify fluid compatibility.