Description
D901 Flow Measurement Device (FMD) – DZR Copper Alloy
Precision Flow Measurement for HVAC Hydronic Systems
The Crane Fluid Systems D901 Flow Measurement Device (FMD) is a precision-engineered balancing component designed for accurate flow measurement and commissioning of closed-loop heating and chilled water systems. Manufactured from high-quality DZR (Dezincification Resistant) copper alloy, the D901 provides reliable long-term performance while ensuring corrosion resistance in demanding building service applications. It is widely used in commercial buildings, hospitals, hotels, data centres, universities, and industrial HVAC installations.
Unlike conventional balancing devices, the D901 incorporates a fixed square-edged orifice with integral pressure test points, allowing technicians to accurately determine system flow rates using differential pressure measurements. This enables fast system commissioning, simplified maintenance, and improved hydraulic balancing without interrupting system operation.

Key Features
- Precision Flow Measurement Device (FMD)
- Sizes available from DN15 to DN50 (½” to 2″)
- Pressure rating: PN25
- Operating temperature: 10°C to 120°C
- Manufactured from DZR Copper Alloy for excellent corrosion resistance
- Integral square-edged orifice for repeatable flow measurement
- Pressure test points compatible with P84 insertion probes
- Flow measurement accuracy of ±5%
- WRAS Approved for potable water applications
- Female inlet and male threaded outlet connections
- BIM and CAD files available for engineering design integration.
Benefits
Accurate Commissioning
The D901 enables engineers to verify design flow rates quickly and accurately, ensuring that every branch of the hydronic system receives the correct water flow.
Improved Energy Efficiency
Correct hydraulic balancing minimizes pump energy consumption, reduces unnecessary flow rates, and improves overall HVAC efficiency.
Reliable Long-Term Performance
The use of DZR copper alloy provides outstanding resistance to dezincification and corrosion, extending service life even in aggressive water conditions.
Simplified Maintenance
Integrated pressure test points allow routine performance verification without dismantling the piping system, reducing maintenance time and operating costs.
Typical Applications
The D901 Flow Measurement Device is suitable for:
- Chilled water systems
- Heating water systems
- Commercial HVAC installations
- District heating networks
- Data centres
- Hospitals
- Hotels
- Office buildings
- Universities
- Industrial process water systems.
Technical Specifications
| Parameter | Specification |
|---|---|
| Product | D901 Flow Measurement Device (FMD) |
| Material | DZR Copper Alloy |
| Size Range | DN15 – DN50 |
| Pressure Rating | PN25 |
| Temperature Range | 10°C to 120°C |
| Flow Accuracy | ±5% |
| Connections | Female inlet × Male threaded outlet |
| Test Points | P84 Pressure Test Points |
| Approval | WRAS Approved |
Why Choose the Crane D901?
The D901 has been developed specifically for engineers who require dependable and repeatable flow measurement during commissioning and system maintenance. Its precision fixed-orifice design delivers greater consistency than many traditional measurement methods while reducing installation complexity.
Combined with Crane Fluid Systems’ comprehensive range of balancing valves, the D901 forms an integral part of a complete hydronic balancing solution that helps improve comfort, optimize pump performance, and reduce building energy consumption





