Horizontal Multistage Pump with Integrated VFD and Intelligent PID Control — Eight Built-In Protection Functions for Worry-Free Constant Pressure Operation
Water demand in any building fluctuates by the hour. Morning showers spike consumption, midday lulls reduce it, and evening surges push it back up. A fixed-speed pump cannot track these changes. It delivers full pressure at full flow or no pressure at all — and your taps feel the difference every time.
The HLE constant pressure water pump from Anhui Hongjiu Water Pump Equipment Co., Ltd. solves this problem by integrating a variable frequency drive (VFD) directly onto the proven HL hydraulic platform. The result is a pump that monitors system pressure in real time and adjusts motor speed automatically to maintain a rock-steady setpoint — regardless of how many taps, showers, or appliances are running simultaneously.
Eight Smart Features Built Into Every HLE Constant Pressure Water Pump
The HLE is engineered for hands-free operation. Eight intelligent features work together to deliver consistent pressure, protect your equipment, and minimize energy consumption:
- Fully Automatic Start/Stop — The pump starts when demand is detected and stops automatically when all taps close. No manual switching, no wasted energy during idle periods.
- Clean and Hygienic — All over-current parts are AISI 304 stainless steel, ensuring minimal secondary contamination of the conveyed medium. Safe for potable water supply.
- Precision Constant Pressure — A high-accuracy PID controller with real-time stepless speed regulation eliminates pressure fluctuations. Occupants experience consistent water pressure at every tap.
- Water Shortage Protection — Dry-run detection monitors suction conditions continuously. If the water source is depleted, the pump stops automatically to prevent seal and bearing damage.
- Multiple Electrical Protections — Over-current, overload, over-voltage, under-voltage, and phase-loss protection safeguards the motor and VFD from supply anomalies and electrical faults.
- Adjustable Pressure Setting — Users set target pressure directly through the control interface. The pump maintains that setpoint automatically, making it easy to adjust for different building configurations or seasonal demand changes.
- High Efficiency, Low Noise — New-generation energy-saving motors combined with optimized controller output deliver lower energy consumption and quieter operation compared to conventional fixed-speed installations.
- Easy Operation — The HLE ships factory-tested and pre-configured. Users connect water and power, set the desired pressure, and the pump handles everything else automatically.
Technical Specifications
| Parameter | HLE VFD Value |
|---|---|
| Flow Rate (Q) | 0 – 28 m³/h |
| Head (H) | 5 – 65 m |
| Frame Sizes | HL2, HL4, HL8, HL12, HL16, HL20 |
| Working Pressure | 10 bar (1.0 MPa) |
| Medium Temperature | 0°C to +90°C |
| Pump Body Material | AISI 304 Stainless Steel |
| Impeller Material | AISI 304 Stainless Steel |
| Mechanical Seal | Silicon carbide / graphite |
| Control Mode | Constant-pressure (PID) / Constant-speed (dual mode) |
| VFD Integration | Backpack design, factory-installed |
| Voltage Options | Single-phase 220V / Three-phase 380V |
| Protection Functions | 8 (auto start/stop, dry-run, over-current, overload, over-voltage, under-voltage, phase-loss, over-temperature) |
For complete performance curves, wiring diagrams, and dimension drawings for all frame sizes, contact our engineering team.
Backpack VFD Design — Compact, Simple, Reliable
The HLE mounts the variable frequency drive in a “backpack” configuration directly on the pump motor. This integrated design offers several practical advantages over traditional pump-plus-external-panel installations:
- Compact footprint — no separate control panel to mount on the wall, no additional floor space required
- Pre-wired and pre-configured — the VFD is connected to the motor and pressure sensor at the factory, eliminating on-site wiring errors
- Reduced installation time — connect water piping and electrical supply, set the target pressure, and the system is operational
- Lower total cost — no external control panel, no separate VFD procurement, no third-party commissioning
This plug-and-play approach is particularly valuable for residential installations where specialized controls expertise may not be available on site.
Constant Pressure vs. Constant Speed — Dual Mode Flexibility
The HLE offers two operating modes selectable through the control interface:
| Mode | How It Works | Best For |
|---|---|---|
| Constant Pressure | PID controller adjusts motor speed in real time to maintain a fixed discharge pressure setpoint, regardless of flow demand | Variable-demand systems: villas, apartments, hotels, commercial buildings |
| Constant Speed | Motor runs at a fixed frequency, similar to a standard fixed-speed pump but with full VFD protection functions active | Systems with near-steady demand where protection features are still valued |
Switching between modes is done through the digital interface — no rewiring or parameter changes required. This flexibility means the same pump can serve applications with wildly different demand profiles simply by selecting the appropriate mode.
Applications
Villa Water Supply Boosting
The HLE is an ideal constant pressure water pump for luxury villas and multi-bathroom homes. Multiple occupants may use showers, run washing machines, and irrigate gardens simultaneously — causing wide demand swings throughout the day. The HLE maintains steady pressure at every tap, regardless of how many fixtures are in use. The single-phase 220V option makes it compatible with standard residential electrical supply.
High-Rise Apartment Water Supply
For multi-story residential buildings, maintaining consistent pressure on upper floors is a persistent challenge. The HLE automatically compensates for elevation loss and friction head, delivering uniform pressure from the ground floor to the top. During peak morning and evening hours when many residents use water simultaneously, the pump ramps up. During overnight lows, it drops to near-zero speed, saving energy without sacrificing availability.
Hotel and Resort Spa Circulation
Hotels, resorts, and wellness centers demand quiet, reliable water pressure for guest comfort. The HLE’s low-noise operation minimizes disturbance, while the automatic constant pressure ensures consistent shower and spa performance even during full-occupancy periods. The VFD protection suite prevents unexpected shutdowns that could disrupt guest services.
Frequently Asked Questions
What protection functions are included in the HLE constant pressure water pump?
The HLE includes eight protection functions: automatic start/stop, water shortage (dry-run) protection, over-current protection, overload protection, over-voltage protection, under-voltage protection, phase-loss protection, and over-temperature protection. These functions operate automatically from the moment the pump is powered on and require no user configuration.
How do I set the target pressure on the HLE?
Pressure is set directly through the digital control interface on the VFD controller. The display shows the current system pressure and the target setpoint simultaneously. Users adjust the setpoint using the interface buttons. The PID controller then maintains that pressure automatically. For detailed setup instructions, refer to the product manual or contact our technical support team.
Is the HLE constant pressure water pump available in single-phase 220V?
Yes. The HLE is available in both single-phase 220V and three-phase 380V configurations across the full range of frame sizes (HL2 through HL20). The single-phase option is designed for residential installations where three-phase power is not available, making the HLE suitable for villas, homes, and small commercial buildings on standard domestic electrical supply.
Related Products
The HLE is part of the HL Horizontal Multistage Pump family. Depending on your application requirements, consider these alternatives:
- Fixed-speed application, lower upfront cost? The HL Standard Pump delivers the same hydraulic performance without the VFD premium — ideal for constant-duty water transfer and simple circulation systems.
- Outdoor installation, no shelter available? The HLES Rain-Proof Pump wraps the HLE in a stainless steel weatherproof enclosure, providing rain, dust, and theft protection for remote and exposed sites.
Request a Quote
Tell us your required pressure setpoint, peak flow rate, building type, and electrical supply. Our engineering team will select the optimal HLE model and deliver a competitive quotation with performance data — typically within 24 hours.
