Product Overview
The Rexroth Z4S 16-20 (Material Number R900425901) is a pilot-operated check valve from the Z4S series, engineered for leak-free load holding and controlled load lowering in industrial hydraulic systems. As a modular (sandwich) plate design, it mounts directly between a directional control valve and its subplate, functioning as a pilot-controlled blocking element that permits free flow in one direction and blocks reverse flow until a pilot pressure signal opens the poppet. The valve is released hydraulically via an external pilot line, allowing controlled return flow only when the directional valve is actuated. With a size 16 (NG16 / CETOP 7) interface and a nominal flow rating of 20 (up to 450 L/min), the Z4S 16-20 is a high-flow, pressure-rated component suited to demanding load-holding circuits in presses, injection molding machines, and heavy industrial machinery.
Technical Specifications
| Parameter | Specification / Feature |
|---|---|
| Component Type | Pilot Operated Check Valve (Modular / Sandwich Plate Design) |
| Model Designation | Z4S 16-20 / R900425901 |
| Nominal Size | NG16 (CETOP 7 / ISO 4401-07 interface) |
| Flow Rating Code | 20 (nominal flow up to approx. 450 L/min) |
| Operating Pressure | Up to 315 bar (working pressure, port-dependent) |
| Pilot Pressure Ratio | Pilot-to-load area ratio per Rexroth Z4S standard (approx. 1:4.5) |
| Mounting & Connection | Modular sandwich mounting, ISO 4401 / CETOP 7 subplate interface |
| Sealing | NBR (Buna-N) seals, standard mineral hydraulic oil compatible |
| Fluid Compatibility | Mineral oil HL / HLP per DIN 51524, viscosity 10–800 mm²/s |
Engineering Features & Advantages
- Leak-Free Load Holding: The seated poppet design provides zero-leak blocking of reverse flow, securely holding suspended loads and preventing drift in vertical or clamping circuits.
- Hydraulically Pilot Released: External pilot pressure opens the poppet against the load, enabling controlled lowering and smooth decompression of the actuator circuit.
- Modular Sandwich Construction: Compact plate design mounts directly between directional valve and subplate, minimizing piping, leak points, and installation footprint.
- Industrial Reliability: Designed for dependable long-term operation in demanding industrial environments, with quality bearings and sealing systems ensuring extended maintenance intervals.
- Direct Fit Replacement: Precision-manufactured to original REXROTH specifications for direct replacement, minimising downtime and eliminating fitment issues.
Typical Industrial Applications
With a size 16 (NG16 / CETOP 7) interface and a nominal flow rating of 20 (up to 450 L/min), the Z4S 16-20 is a high-flow, pressure-rated component suited to demanding load-holding circuits in presses, injection molding machines, and heavy industrial machinery.
PRODUCT IMAGES
REXROTH Z4S 16-20/ / R900425901 Pilot Operated Check Valve
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- Authentic & Fully Tested: 100% bench tested for hydraulic response, pressure rating, and null-bias stability before dispatch.
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- Peace of Mind: Covered by our 12-Month Replacement Warranty.
Shop the genuine REXROTH Z4S 16-20/ / R900425901 Pilot Operated Check Valve. This German-made hydraulic component features a robust poppet design, delivering leak-free, reliable fluid control for heavy-duty industrial systems.