R900244765 4WRZ25W6-325-7X/6EG24N9ETK4/D3M Rexroth Germany hydraulic servo proportional valve

Q: What is the main difference between this valve and the previous R900958570?

A:​ This valve (R900244765) uses internal pilot oil return (to T, "ET" code), which eliminates the need for an external Y-port drain line. The previous model required an external Y-port connection. This simplifies plumbing but requires that the T-port backpressure remains below 30 bar​ to ensure proper pilot valve function.

Q: What does the /D3M suffix mean?

A:​ The /D3​ suffix indicates an integrated pressure reducing valve (ZDR 6)​ for regulating pilot pressure. The /M​ suffix specifies standard NBR seals.

Q: How does the pilot oil configuration work?

A:​ This valve (/6EG24N9ETK4) uses internal pilot oil supply (from main P port) and internal pilot oil return (to main T port). This "ET" configuration is the most convenient as it requires no external pilot lines, but you must ensure the main tank line (T-port) backpressure is controlled.

Q: Why choose this specific configuration?

A:​ This model is ideal for high-flow applications (325 L/min) requiring simplified plumbing. The internal pilot drain (ET)​ reduces the number of hydraulic connections, while the integrated /D3 pressure reducer​ protects the pilot stage from system pressure fluctuations.

Q: What is the critical installation note?

A:​ Since the pilot stage drains internally to T, you must ensure the main T-port backpressure is below 30 bar. High backpressure on T can prevent the pilot valve from draining properly, causing erratic main stage operation. Maintain high oil cleanliness (recommended NAS 1638 Class 8 or better for the main stage).