R900721116 4WRZE16W8-150-7X/6EG24N9ETK31/F1D3M German Rexroth servo proportional valve

FAQ:

1. Q: What is the main difference between this valve and the previous R900757605?

   A:​ This valve (R900721116) 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.

2. Q: What does the /F1D3M suffix mean?

   A:​ The /F1​ suffix indicates 4–20 mA current control input​ (ideal for noise-immune industrial signals). The /D3​ suffix indicates an integrated pressure reducing valve (ZDR 6)​ for regulating pilot pressure. The /M​ suffix specifies standard NBR seals.

3. Q: How does the pilot oil configuration work?

   A:​ This valve (/6EG24N9ETK31) 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.

4. Q: Why choose this specific configuration?

   A:​ This model is ideal for applications requiring smooth control (W8 spool) with simplified plumbing. The 4–20 mA control (/F1)​ offers good noise immunity, and the internal pilot drain (ET)​ reduces the number of hydraulic connections. The integrated /D3 pressure reducer​ protects the pilot stage from system pressure fluctuations.

5. 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).