Davey's Horizontal Multistage Water Pump With Pressure Switch - HM270-25P
Key features:
- Standard automatic pressure system type.
- Suitable for 4 storey households and offices.
- For household, garden, farming, and agricultural use.
- 24 months warranty for pump, motor & controller.
(24 + 6 additional months with e-Warranty scheme) - Fixed pressure setting on every usage.
- Easy installation, no setting required.
Classified As:
Overview of Davey's Horizontal Multistage Water Pump With Pressure Switch - HM270-25P
The HM270-25P is the largest model in the HM Horizontal Multistage series by Davey Water Products Pty Ltd. Engineered for demanding commercial, industrial, and heavy-duty applications, this high-performance pump is equipped with an integrated motor that delivers large volumes of pressurised water over long distances with exceptional efficiency.
For residential use, the HM270-25P is capable of supplying water to buildings of up to four storeys while maintaining consistent water pressure throughout an extensive plumbing network. Unlike conventional pressure pumps, this Horizontal Multistage model is fitted with an integrated pressure switch and is designed to operate in conjunction with a pressure tank. Together, they minimise continuous pump cycling, enhancing operational efficiency while extending the service life of the system.
Every hydraulic component of the HM270-25P Horizontal Multistage electropump is manufactured using Davey’s automated lean production process, where laser-precise assembly ensures exceptional build quality and performance. Once production is completed, each unit undergoes rigorous testing to verify its reliability, efficiency, and operational consistency before reaching the end user. This stringent quality assurance process reflects Davey’s commitment to delivering dependable pumping solutions that consistently meet customer expectations.
As its name suggests, the HM270-25P Horizontal Multistage water pump is designed with a horizontal inlet configuration, allowing clean fluids to enter smoothly through a level-mounted arrangement. Inside the pump, water passes through multiple stages of precision-engineered impellers and diffusers. Pressure is gradually increased at each stage before the fluid is discharged through the outlet with a powerful and consistent flow, making the pump suitable for applications requiring high pressure over extended distances.
Premium stainless steel is extensively incorporated throughout the HM270-25P’s construction. Most hydraulic components are manufactured from SS304 stainless steel, while a variety of precision-sized O-rings provide secure sealing to minimise the risk of water leakage. The pump shaft is constructed from higher-grade SS316 stainless steel, offering superior corrosion resistance, enhanced durability, and long-term reliability even under demanding operating conditions.
Powering the HM270-25P is a Totally Enclosed Fan Cooled (TEFC) motor, housed within a fully enclosed one-piece construction. This design effectively dissipates heat during operation while protecting the motor against dust, moisture, and accidental external contact, ensuring safe, reliable, and long-lasting performance.
Warranty: The HM270-25P Horizontal Multistage water pump is backed by a two-year manufacturer’s warranty. Customers who register under the e-Scheme will also receive an additional six months of warranty coverage, providing extended protection and greater peace of mind.
HM270-25P's Method of Identification
To facilitate efficient product traceability from manufacturing through to inventory control and worldwide distribution, a standardised model naming system is applied to the HM270-25P Horizontal Multistage pump in accordance with the product identification practices of Davey Water Products and Waterco. By adopting this structured designation, product recognition is simplified, quality control procedures are strengthened, and compliance with ISO quality management and auditing standards is effectively supported.
The HM270-25P model code is defined as follows:
1) HM – Designates the Horizontal Multistage pump series.
2) 270 – Refers to the pump’s nominal flow capacity of 270 litres per minute (L/min) at its Best Efficiency Point (BEP).
3) 25 – Identifies the pump’s 2.5 kW motor power output.
4) P – Specifies that the pump is equipped with a factory-installed pressure switch.
The HM270-25P model designation serves as a concise identifier that communicates the pump’s principal performance characteristics and configuration.
Within the model code, the prefix “HM” signifies that the unit belongs to Davey’s Horizontal Multistage pump series. The number “270” represents the pump’s nominal flow capacity of 270 litres per minute (L/min) at its Best Efficiency Point (BEP), while “25” denotes the 2.5 kW motor power rating. Completing the designation, the suffix “P” indicates that the pump is factory-equipped with an integrated pressure switch.
In addition to describing the pump’s technical configuration, the HM270-25P model designation, together with its unique Stock Keeping Unit (SKU), plays an important role in product identification across Davey Malaysia’s manufacturing, warehousing, distribution, and after-sales service network. By implementing a standardised naming convention, inventory control is improved, order fulfilment becomes more accurate, warehouse operations are streamlined, and complete product traceability is maintained throughout the supply chain.
The model designation also provides practical benefits for installers, plumbers, and maintenance personnel by enabling the installed pump to be identified quickly and accurately. As a result, the correct replacement components can be specified with confidence, servicing procedures can be carried out more efficiently, and maintenance downtime is minimised. These advantages contribute to sustaining the long-term reliability, operational efficiency, and service life of the HM270-25P Horizontal Multistage water pump.
Attachment
Mechanical Pressure Switch
As a practical alternative to the Torrium2 Intelligent Pressure Controller, the HM270-25P may also be supplied with a conventional mechanical pressure switch. Offering a dependable and economical solution, this configuration automatically controls pump operation by responding directly to fluctuations in the system’s water pressure.
Rather than relying on electronic sensors, microprocessors, or adaptive control functions, a mechanical pressure switch operates using a spring-loaded diaphragm coupled with a set of electrical contacts. As the system pressure rises or falls, the diaphragm actuates the switch to start or stop the pump at predetermined pressure settings, ensuring consistent automatic operation through a simple and proven mechanical design.
Pump operation is controlled by two predetermined pressure settings: the cut-in pressure and the cut-out pressure. Whenever water is drawn from the system and the pressure falls below the cut-in threshold, the mechanical pressure switch closes the electrical circuit to start the pump automatically. The pump then continues running as it restores pressure throughout the water system. Once the preset cut-out pressure has been achieved, the switch opens the electrical circuit, shutting down the pump until a further drop in pressure signals the next operating cycle.
While it does not offer the advanced features of an electronic pressure controller, a conventional mechanical pressure switch delivers reliable and fully automatic pump control through a simple, proven operating principle. Its robust construction, ease of maintenance, and cost-effective performance make it a preferred solution for a broad range of residential and light commercial water pressure applications.
Example of Mechanical Pressure Switch Operation
- Below 20 psi (1.4 bar): When the system pressure falls below the preset cut-in pressure, the mechanical pressure switch closes the electrical circuit, automatically starting the HM270-25P to restore water pressure.
- Between 20 and 40 psi (1.4–2.8 bar): As water is consumed, the pump continues operating to maintain and replenish system pressure until the preset cut-out pressure is achieved.
- At 40 psi (2.8 bar): Once the system reaches the cut-out pressure, the pressure switch opens the electrical circuit, stopping the pump. The pump remains off until water usage causes the pressure to drop below the cut-in setting, initiating the next operating cycle.
Important: When the HM270-25P is operated with a mechanical pressure switch, the installation of a pressure tank is essential. The pressure tank stores a reserve of pressurised water, allowing minor water demands to be supplied without immediately activating the pump. By reducing unnecessary start-stop cycles, pump cycling is minimised, system efficiency is improved, and the service life of the pressure switch, pump, and other connected components is extended.
Pressure Tank
A pressure tank is a sealed pressure vessel designed to store water under pressure by utilising compressed air. When installed alongside a mechanical pressure switch, it provides a reserve of pressurised water that allows small water demands to be met without immediately starting the pump. As a result, pump cycling is significantly reduced, overall system efficiency is improved, and the operational lifespan of the pump and its associated components is extended.
The interior of the pressure tank is divided into two separate chambers by a durable rubber diaphragm. One chamber is filled with water, while the other contains a pre-charged volume of compressed air. As the Horizontal Multistage pump delivers water into the tank, the air chamber is compressed by the incoming water, storing energy in the form of hydraulic pressure. This stored pressure is then available to supply the water system until the pressure falls to the pump’s cut-in setting, at which point the pump automatically resumes operation.
When water is required, opening a tap, shower, or any other outlet allows the compressed air inside the pressure tank to discharge the stored water into the plumbing system. Because a supply of pressurised water is already available, the Horizontal Multistage pump remains idle during minor water demand, reducing unnecessary pump starts.
As water continues to leave the tank, the internal pressure progressively declines. Once the system pressure reaches the preset cut-in value, the mechanical pressure switch automatically closes the electrical circuit, bringing the pump into operation. Water is then delivered to both the plumbing system and the pressure tank until the preset cut-out pressure is attained. At that point, the switch interrupts the electrical circuit, stopping the pump and completing the operating cycle.
This automatic sequence ensures a stable and reliable water supply while limiting excessive pump cycling. By reducing the frequency of motor starts and minimising mechanical stress on system components, overall operating efficiency is enhanced and the service life of the pump, pressure switch, and associated equipment is prolonged.
Certification
The HM270-25P Horizontal Multistage water pump, together with Davey’s wider Horizontal Multistage range, is engineered and produced to meet a selection of globally recognised standards and certification requirements. These certifications validate the pump’s commitment to dependable performance, operational safety, manufacturing quality, and long-term reliability, while enabling compliance with international market expectations.
Through alignment with recognised industry standards, Davey’s Horizontal Multistage pumps are able to support installations across various regions while satisfying relevant technical, regulatory, and safety requirements. Each certification provides assurance to customers, engineers, and service professionals that the pump has been developed through controlled engineering processes and manufactured under established quality management practices.
These certifications also represent more than regulatory approval; they reflect Davey’s ongoing focus on innovation, consistency, and product improvement. Strict controls are implemented throughout the design, assembly, and verification stages to ensure every HM270-25P unit achieves reliable hydraulic output, electrical safety, structural durability, and sustained performance throughout its operating life.
SGS Verification: Products verified by SGS (Société Générale de Surveillance) are subjected to independent evaluation to validate compliance with relevant standards and the manufacturer’s declared performance requirements. For Davey’s Horizontal Multistage pump range, verification may involve assessments covering key areas such as hydraulic efficiency, material integrity, electrical safety, and overall operational reliability. This independent review process provides greater confidence that the pump is capable of delivering the specified performance while meeting established quality and safety benchmarks.
European Ecodesign Compliance: Davey’s Horizontal Multistage pumps are engineered to align with applicable European Ecodesign Regulations for water pumps supplied to the European market. These regulations define minimum energy efficiency requirements aimed at reducing energy consumption and promoting the development of more sustainable pumping technologies. Compliance with these requirements reflects Davey’s commitment to producing efficient, environmentally responsible, and performance-focused pump solutions.
Compliance with the Ecodesign framework delivers a range of performance and environmental advantages, including:
- Enhanced hydraulic efficiency through optimised pump operation and improved energy utilisation.
- Lower electricity consumption by reducing unnecessary energy demand during operation.
- Reduced operating expenses as a result of improved energy performance and efficiency.
- Lower greenhouse gas emissions through decreased energy usage and environmental impact.
- Greater environmental sustainability by supporting the development of more responsible and efficient pumping solutions.
Adherence to internationally recognised standards further reinforces the safety, reliability, and performance of Davey’s Horizontal Multistage pumps. Through compliance with established engineering and quality requirements, potential risks such as mechanical breakdown, water leakage, and electrical safety concerns are minimised, helping to ensure dependable operation throughout the pump’s service life.
International Electrotechnical Commission (IEC): The International Electrotechnical Commission (IEC) establishes internationally recognised standards for electrical and electronic technologies. By complying with relevant IEC requirements, Davey’s Horizontal Multistage pumps are manufactured with electrical systems that undergo appropriate design, evaluation, and testing processes to ensure they meet recognised benchmarks for safety, reliability, and performance.
Applicable IEC standards address key electrical considerations, including:
- Electric motor safety – ensuring motors operate reliably while meeting established protection and performance requirements.
- Electrical insulation and protection – verifying adequate insulation systems and safeguards against electrical risks.
- Control system performance and reliability – supporting consistent operation and dependable interaction between electrical control components.
- Electrical performance testing – confirming that electrical systems function within specified operational parameters.
- Electromagnetic compatibility and system integration – ensuring compatibility with auxiliary equipment, including Variable Frequency Drives (VFDs), while maintaining stable and reliable operation.
Compliance with relevant IEC standards helps reduce electrical risks associated with pump operation, including electric shock, excessive heat generation, short circuits, and potential fire hazards. These requirements ensure that the electrical components within Davey’s Horizontal Multistage pumps are designed to deliver safe, dependable, and consistent performance across various installation conditions and operating environments.
Australian Standards: As an Australian-based manufacturer, Davey develops its products in accordance with applicable Australian Standards that are recognised for establishing requirements in product safety, quality, and performance. Meeting these standards demonstrates that the HM270-25P has been engineered and manufactured according to strict technical and safety criteria, providing confidence to customers across Australia, New Zealand, Southeast Asia, and international markets.
- AS 4020:2005 – Products for Use in Contact with Drinking Water: For applications involving potable water, AS 4020:2005 is a key standard that evaluates the suitability of materials and components intended for contact with drinking water. The assessment determines whether materials release potentially harmful substances, affect water characteristics such as taste, colour, or odour, or compromise overall water quality.
Compliance with AS 4020:2005 confirms that the wetted components incorporated within the Horizontal Multistage pump are suitable for ongoing exposure to potable water. This provides assurance that water quality is preserved during normal operation and that the pump is appropriate for use in drinking water applications where material safety is a critical consideration.
Standards New Zealand: For products supplied to the New Zealand market, Davey designs its pumping solutions in accordance with relevant requirements recognised by Standards New Zealand. Compliance with these requirements supports regulatory acceptance and assures customers that Davey products are developed to meet established expectations for safety, reliability, and performance within New Zealand operating environments.
ISO 9001:2015 – Quality Management Systems:
ISO 9001:2015 is a globally recognised standard that defines requirements for effective Quality Management Systems (QMS). Certification to this standard reflects Davey’s commitment to maintaining consistent manufacturing practices and delivering water pumps and related products that satisfy customer requirements and applicable regulatory obligations.
Through structured quality controls, documented processes, and continuous improvement initiatives, ISO 9001:2015 supports consistency throughout the entire manufacturing process. From production planning to final inspection, these practices help ensure each pump achieves reliable quality, performance, and operational dependability across every manufacturing batch.
ISO 14001 – Environmental Management Systems:
ISO 14001 certification recognises organisations that establish and maintain effective environmental management systems. For Davey, this certification demonstrates an ongoing commitment to responsible manufacturing practices through initiatives focused on improving resource efficiency, reducing waste generation, encouraging recycling where feasible, and minimising the environmental impact associated with production activities.
TÜV SÜD Certification: The HM270 Horizontal Multistage pump series is independently assessed by TÜV SÜD, a globally recognised testing and certification organisation. Through comprehensive evaluation procedures, TÜV SÜD certification provides additional verification that the pump meets relevant requirements relating to safety, quality, performance, and engineering compliance.
Together, these certifications represent Davey’s dedication to engineering excellence, manufacturing reliability, environmental responsibility, and consistent product quality. More than fulfilling regulatory obligations, they provide independent assurance that the HM270-25P has been designed, manufactured, and verified according to internationally recognised standards.
For customers, installers, engineers, and distribution partners, these recognised certifications provide confidence that Davey Horizontal Multistage water pumps are built to deliver dependable operation, consistent performance, and long-term reliability across a wide range of applications and installation conditions.
Consistent Speed, TEFC Motor
The HM270-25P incorporates a Totally Enclosed Fan Cooled (TEFC) motor that is engineered to provide dependable and continuous performance for residential and light commercial water pressure systems. With a fixed-speed operating design, the motor delivers consistent power output while maintaining a high level of protection against external conditions, including dust, moisture, dirt, and other potentially harmful contaminants. This enclosed configuration enhances motor longevity, improves operational reliability, and reduces the need for frequent maintenance.
A key advantage of the TEFC motor design is its ability to isolate internal electrical components from the surrounding environment. By preventing foreign particles and moisture from entering the motor enclosure, the risk of component degradation is significantly reduced. Heat produced during normal operation is efficiently removed through a cooling fan positioned on the motor shaft, which generates airflow across the outer motor frame to dissipate excess heat.
Through effective thermal management and environmental protection, the TEFC motor maintains stable operating conditions for its internal windings and electrical components. This combination of protection and cooling performance allows the HM270-25P to achieve reliable operation, improved durability, and extended service life in a wide range of pumping applications.
The HM270-25P features a dedicated hydraulic chamber that is isolated from the motor assembly through a mechanical seal and backplate arrangement. This separation provides an effective barrier against water transfer into the motor housing during normal pump operation, helping protect sensitive electrical components from moisture exposure. Under standard operating conditions, the motor compartment remains dry and secure, with water entry only expected in the rare occurrence of mechanical seal or backplate damage.
Plug-And-Use Convenience: Supplied as a fully integrated pump and motor unit, the HM270-25P is designed to simplify installation and minimise setup requirements. Once the appropriate plumbing connections and electrical supply have been established, the pump can be placed into service without requiring additional motor adjustments, configuration, or commissioning procedures. This ready-to-install design helps reduce installation complexity while offering greater convenience for both residential users and professional installers.
Proven TEFC Motor Technology: A Totally Enclosed Fan Cooled (TEFC) motor is incorporated into the HM270-25P, providing a reliable and widely proven drive solution for water pumping and industrial applications. The enclosed motor structure protects internal components from external contaminants, including dust, dirt, moisture, and other environmental factors that may affect performance.
During operation, an external cooling fan mounted to the motor shaft generates airflow across the motor housing to effectively dissipate heat. This combination of sealed protection and efficient thermal management helps maintain stable operating conditions, reduces maintenance demands, and supports dependable performance throughout the motor’s service life.
Lower Maintenance, Lower Operating Costs: By combining a durable TEFC motor, corrosion-resistant hydraulic components, and Davey’s established engineering capabilities, the HM270-25P is designed to provide reliable performance with reduced ownership costs over its operational lifespan. Its robust construction helps minimise the effects of environmental exposure, limit component wear, and reduce the need for frequent servicing.
Suitable for residential properties, commercial premises, and light industrial applications, the HM270-25P delivers long-term value through consistent operation, reduced downtime, and dependable service life. Its combination of efficiency, durability, and ease of use makes it a practical solution for applications requiring reliable water pressure performance.
Suction Inlet
The HM270-25P is fitted with a two-inch suction inlet connection that is engineered to provide efficient water entry into the pump’s hydraulic assembly. Although the pump is supplied with a standard inlet configuration, a range of compatible fittings, connectors, and adaptors may be utilised to accommodate varying pipework layouts. This provides greater flexibility during installation and allows the pump to be adapted to different site conditions.
The suction inlet is a critical component within the centrifugal pumping process, as it serves as the initial pathway for water entering the hydraulic system before pressure is generated and flow is distributed throughout the installation. Maintaining the correct inlet size, selecting suitable pipework, and following proper installation practices are essential to achieving smooth fluid movement, reducing flow restrictions, and optimising overall pump efficiency.
Designed as part of Davey’s Horizontal Multistage pump series, the HM270-25P is intended for clean water applications requiring reliable pressure delivery across residential, office, and light commercial settings. With correct installation and operating conditions, the pump provides efficient water transfer, consistent pressure performance, and dependable service for larger properties and systems with increased water demand.
One-Directional Flow Design: The Davey HM270-25P Horizontal Multistage pump incorporates a unidirectional hydraulic flow arrangement, where the electric motor rotates multiple impeller stages to generate the pressure required for efficient water movement through the pump system. This engineered flow path guides clean water in a controlled direction, supporting stable pressure generation and consistent delivery throughout the application.
Reduced Hydraulic Resistance: Within a centrifugal pump system, the design and sizing of the suction inlet have a direct influence on hydraulic efficiency. A correctly sized inlet connection helps reduce friction losses, improves water entry conditions, and minimises restrictions as fluid enters the hydraulic chamber. By allowing smoother water intake, the pump can operate more efficiently while maintaining reliable flow performance.
To achieve optimal operation, the suction pipe size, inlet configuration, and installation method must be properly matched to the pump requirements. A well-designed hydraulic system reduces unnecessary losses, enhances overall efficiency, and helps maintain the long-term reliability and performance of the HM270-25P.
The following table provides a summary of the HM270-25P suction inlet and discharge outlet specifications:
| 240V Single Phase Models | ||
|---|---|---|
| Product Code | Ports | |
| Suction BSP | Discharge BSP | |
| HM270-25 | 2 inch F (50.8mm) | 1 1/2 inch M (38.1mm) |
Volute
The volute within the HM270-25P Horizontal Multistage pump serves as the primary hydraulic casing that encloses, aligns, and supports the internal impeller and diffuser stages. Although the external housing features a compact cylindrical form, the internal water passage is carefully designed with a spiral profile to optimise fluid movement, improve energy conversion, and enhance overall hydraulic efficiency.
Manufactured from robust, high-quality composite materials, the volute is engineered to withstand continuous operating demands while maintaining dimensional stability, mechanical strength, and reliable hydraulic performance over an extended service period.
During pump operation, the volute performs an essential hydraulic function by gathering water discharged from each impeller stage and directing it towards the outlet. Its gradually expanding spiral configuration assists in converting the kinetic energy of high-velocity water into usable pressure energy before discharge. This controlled conversion process reduces unnecessary turbulence, supports efficient pressure development, and enables the HM270-25P to deliver smooth and consistent water flow throughout the system.
The HM270-25P volute combines durable material construction with precision-engineered hydraulic geometry to support efficient pressure generation and consistent water delivery. This carefully developed casing design enables reliable performance across a variety of residential and light commercial applications where stable water pressure is required.
Beyond its hydraulic function, the volute casing also provides structural protection for the internal pumping components. By enclosing the hydraulic assembly, it helps reduce exposure to external contaminants, supports cleaner fluid handling, and minimises the risk of premature component deterioration. This protective function contributes to improved system reliability and extended operational durability during continuous pump operation.
Energy Transfer Process: The HM270-25P generates pressure through a multi-stage energy conversion process driven by its electric motor and impeller assembly. As the motor rotates the impellers, mechanical energy is transferred into the water, increasing fluid velocity as it moves through each hydraulic stage. The rotating impellers use centrifugal force to accelerate the water outward into the surrounding diffuser and volute passages.
As the high-velocity water enters the volute, the gradually expanding flow channel slows the movement of the fluid while converting kinetic energy into pressure energy. This controlled reduction in velocity allows pressure to build progressively, resulting in a smooth and stable discharge flow from the pump outlet.
This process follows established fluid mechanics principles, including the relationship between fluid velocity, pressure, and energy represented by Bernoulli’s equation. Through precise hydraulic design and efficient energy conversion, the HM270-25P is able to achieve dependable pressure performance while maintaining efficient water transfer across a range of applications.
Water-Filled Operation And Air Removal: For reliable operation, the HM270-25P hydraulic chamber and internal flow passages must remain filled with water to allow continuous movement through the impeller stages. Maintaining proper priming conditions is essential, as trapped air within the hydraulic system can interrupt fluid flow, reduce pumping efficiency, and affect overall performance.
Air accumulation around the impeller area may contribute to cavitation, a hydraulic phenomenon where vapour bubbles are created and collapse due to rapid pressure variations within the fluid. Prolonged cavitation can result in increased operating noise, reduced hydraulic output, and accelerated wear of internal pump components.
By maintaining stable water-filled conditions and effective hydraulic operation, the HM270-25P delivers consistent pressure output, efficient performance, and dependable service life throughout its intended operating applications.
Impeller And Diffuser
The HM270-25P Horizontal Multistage water pump utilises closed-type impellers that are precisely secured to the pump shaft to provide efficient hydraulic energy transfer and controlled fluid movement. Designed with enclosed front and rear shrouds, these impellers create a defined internal flow channel that directs water smoothly through each stage of the pump while assisting in the management of axial forces produced during operation.
Enhanced Hydraulic Performance: The closed impeller configuration allows water to travel through the engineered vane passages with minimal disruption before moving towards the subsequent hydraulic stage or final discharge point. By maintaining a controlled flow path and reducing turbulence within the impeller assembly, the design helps minimise hydraulic losses, improve energy conversion efficiency, and support consistent pressure development.
Through this optimised impeller design, the HM270-25P achieves stable water flow characteristics, reliable pressure output, and efficient operation across residential and light commercial water pressure applications.
Closed Impeller Application
Located within the volute chamber, the HM270-25P’s impellers and diffusers are assembled through a sequence of precision-manufactured stage bodies. These components, sometimes referred to as protection brackets, serve as structural supports that secure the hydraulic elements while maintaining accurate positioning throughout pump operation.
The precise arrangement of the stage bodies ensures that each impeller and diffuser remains correctly aligned, allowing the pump to maintain stable performance under high-speed rotation and continuous duty conditions. As water passes through each individual hydraulic stage, the controlled flow path enables pressure to be increased progressively, resulting in efficient pressure generation and consistent discharge performance.
Through its multi-stage hydraulic configuration, the Horizontal Multistage water pump is capable of delivering reliable pressure enhancement across a broad range of applications. From residential water outlets such as taps and showers to larger domestic, commercial, and water distribution systems, the HM270-25P provides stable flow, dependable pressure, and efficient operation where consistent water delivery is required.
Reduced Risk of Cavitation: The closed impeller design used in the HM270-25P supports a smoother and more controlled flow path through the hydraulic passages, helping to reduce unstable flow conditions that may contribute to air entrainment and pressure variations. By maintaining consistent fluid movement between stages, the impellers help minimise the likelihood of cavitation occurring within the pump.
Reducing cavitation-related effects helps protect critical hydraulic components from excessive vibration, accelerated wear, and loss of pumping efficiency. Through careful integration within the multi-stage hydraulic system, the closed impeller arrangement contributes to reliable pressure generation and stable performance across demanding residential and commercial water applications.
Extended Service Life: The closed impeller configuration also assists in managing hydraulic forces generated during operation. By reducing axial thrust and lowering mechanical loading on key components such as the pump shaft and bearings, unnecessary stress is minimised throughout the pumping assembly.
This improved force balance helps reduce component wear, decrease maintenance requirements, and enhance overall system reliability. As a result, the HM270-25P Horizontal Multistage centrifugal pump is designed to provide long-term durability and dependable operation for continuous water supply requirements.
SS304 Stainless Steel Construction: The impellers and diffusers incorporated into the HM270-25P are manufactured from high-quality SS304 stainless steel, selected for its corrosion resistance, mechanical strength, and suitability for continuous water contact. This material choice helps preserve the structural integrity and hydraulic performance of the internal components throughout the pump’s operating life.
Smooth Hydraulic Surface Finish: Each impeller is precision-machined and finished with a smooth surface profile to reduce friction losses and promote efficient water movement through the hydraulic stages. By limiting turbulence and unnecessary resistance, the stainless steel impeller design supports improved energy transfer, stable pressure output, and efficient pump operation.
Excellent Thermal Stability: SS304 stainless steel provides reliable dimensional stability across a broad range of operating temperatures. Whether handling cold or warm clean water, the impellers and diffusers maintain their structural strength with minimal effects from thermal expansion or contraction.
This thermal performance enables the HM270-25P to maintain consistent hydraulic characteristics under changing operating conditions, ensuring reliable pressure delivery and extended service life for residential, commercial, and light industrial applications.
Generator Defense With Backplate And Mechanical Seal
The backplate and mechanical seal assembly within the HM270-25P Horizontal Multistage pump serves as a critical protective interface between the hydraulic chamber and the electric motor. Located between the water-carrying section and the motor housing, this assembly forms a secure barrier that helps prevent pressurised water from entering the electrical compartment. By maintaining effective separation between these two areas, the design reduces the potential for moisture-related electrical faults, short circuits, and motor damage.
To achieve reliable sealing performance, the assembly is engineered with precision sealing components, including gaskets, sealing washers, and other integrated sealing elements where required. These components work collectively to maintain a tight, leak-resistant interface during operation, ensuring the hydraulic and electrical sections remain properly isolated.
Through this robust separation system, the HM270-25P benefits from enhanced operational safety, improved reliability, and increased durability. The backplate and mechanical seal arrangement plays an important role in protecting critical motor components while supporting consistent performance throughout the pump’s service life.
As the impeller stages generate centrifugal force to move water through the hydraulic system and towards the discharge outlet, the backplate and mechanical seal assembly continue to provide a protective barrier between the water-filled chamber and the electric motor housing. This separation prevents fluid exposure to sensitive electrical components, helping maintain safe operation and reducing the risk of moisture-related motor faults.
Beyond its sealing function, the backplate and mechanical seal arrangement also supports the mechanical integrity of the pump assembly by assisting in the accurate positioning of the pump shaft. Maintaining proper shaft alignment during rotation helps control vibration, limits unnecessary shaft movement, and promotes smoother operation of the rotating components.
By combining hydraulic protection with mechanical support, the backplate and mechanical seal assembly contribute significantly to the overall reliability and longevity of the HM270-25P Horizontal Multistage water pump. This integrated design helps ensure consistent performance, reduced component stress, and dependable operation throughout the pump’s service life.
O-Ring And Spacers
O-rings are integrated throughout the HM270-25P Horizontal Multistage water pump as essential sealing elements that maintain secure connections between individual components. By forming tight, reliable sealing points, these rings help contain pressurised water within the hydraulic system, reduce the risk of leakage, and preserve the pump’s overall operating efficiency and performance.
The HM270-25P utilises O-rings manufactured from EPDM (Ethylene Propylene Diene Monomer) rubber, a high-performance elastomer selected for its excellent resistance to heat, water, ageing, and environmental exposure. Compared with standard sealing materials, EPDM provides enhanced durability and maintains its sealing properties over extended periods, making it particularly suitable for continuous water applications and demanding operating conditions.
Multiple EPDM O-rings are positioned at critical sealing locations throughout the pump assembly, including interfaces around the volute casing and hydraulic components. These precision-fitted seals provide effective isolation of pressurised water, support reliable hydraulic operation, and help minimise maintenance requirements by reducing the likelihood of leaks and premature component degradation.
Through the use of durable sealing materials and carefully engineered placement, the O-ring system contributes to the HM270-25P’s long-term reliability, consistent performance, and extended operational service life.
O-rings are strategically positioned throughout the HM270-25P Horizontal Multistage water pump to create dependable sealing points between interconnected components. These precision-fitted seals help prevent water leakage at internal joints and interfaces, preserving hydraulic containment, maintaining system efficiency, and ensuring stable pump performance during operation.
The O-rings are manufactured from EPDM (Ethylene Propylene Diene Monomer) rubber, a durable elastomer selected for its strong resistance to heat, continuous water exposure, ageing, and environmental factors. Compared with many conventional sealing materials, EPDM provides improved long-term resilience and maintains its sealing effectiveness under demanding operating conditions, including applications involving elevated temperatures and prolonged water contact.
Within the HM270-25P, multiple EPDM O-rings are installed at key sealing locations throughout the hydraulic assembly, including areas surrounding the volute casing and internal pump components. This comprehensive sealing arrangement helps retain pressurised water within the hydraulic system, reduces the possibility of leakage, and supports the pump’s overall durability, reliability, and service life.
Spacers For Stable Operation: Precision-engineered spacers are incorporated between selected rotating and stationary components within the HM270-25P to maintain accurate internal clearances throughout the hydraulic assembly. By controlling the distance between moving parts, these components help prevent unwanted contact, minimise friction, and reduce mechanical wear during continuous operation.
Maintaining precise spacing and alignment allows the hydraulic components to operate smoothly while reducing stress on critical parts. This contributes to improved efficiency, enhanced reliability, and longer component life by protecting internal assemblies from premature wear or damage.
In addition to their spacing function, precision spacers assist in stabilising the rotating assembly by limiting unnecessary movement and reducing vibration. Improved mechanical stability helps minimise operating stress, supports smoother pump performance, and extends the service life of important components such as bearings and other rotating elements.
Operating Limits of HM270-25P Water Pump
| Operating Limits | |
| Maximum continuous flow rate | 200L / min (53 US gallons) |
| Maximum operating pressure | 700 kPa* (102 psi) |
| Maximum current | 10 amp |
| Cut-in pressure range | 80% of pump shut-off head |
| Maximum water temperature | 65°C (149°F) |
*Maximum Operating Pressure: The system’s maximum operating pressure can be increased up to 820 kPa, subject to the pressure rating and specifications of the optional pressure tank selected for installation.
*L (Litres): The symbol L refers to litres, the standard metric unit used for measuring volume capacity.
*kPa (Kilopascal): The kilopascal (kPa) is a metric pressure unit widely used in hydraulic, engineering, and water management applications to define system pressure levels.
*psi (Pounds per Square Inch): The pound per square inch (psi) is an imperial pressure measurement unit commonly used in pump, plumbing, and water supply systems to indicate pressure values.
*A (Ampere): The ampere (A) is the SI unit of electrical current, representing the movement or flow rate of electric charge through an electrical circuit. It is commonly referred to as “amp” in electrical applications.
* °C and °F (Temperature Units): Degrees Celsius (°C) and degrees Fahrenheit (°F) are temperature measurement units used to describe thermal conditions. Celsius is the internationally recognised standard unit, while Fahrenheit is primarily used in the United States and selected regions.
Hydraulic Performance of Davey's HM270 Horizontal Multistage Pump With Pressure Switch
| Single Phase Models | HM270 |
| Motor:P1 kWP2 kW | HM270-19P – P1 kW: 2.4HM270-19P – P2 kW: 1.9HM270-25P – P1 kW: 3.2HM270-25P – P2 kW: 2.5 |
| Amps:RunStart | HM270-19P – Run: 10HM270-19P – Start: 40HM270-25P – Run: 13.8HM270-25P – Start: 66 |
| Ports (BSP):SuctionDischarge | All – Suction: 2 FAll Discharge – 1.5 F |
| Nominal operating pressure (kPa) | HM270-19P: 200HM270-25P: 250 |
| Maximum pump pressure (kPa) | HM270-19P: 300HM270-25P: 400 |
| Tank air pre-charge (kPa) | HM270-19P: 180HM270-25P: 230 |
| Nominal flow (L / min) | All in 270 L / min (71 US gallons) |
Electrical Data
| Pump | |
| Speed | 2900 rpm |
Supply voltage
| 230±10% 415±10% |
| Supply frequency | 50 Hz |
Enclosure class
| IP55 IP56 |
| Insulation class | Class F |
*RPM (Revolutions Per Minute): The abbreviation RPM indicates the rotational speed of the pump motor or shaft, representing the number of complete rotations performed within one minute. This measurement is used to describe the operating speed of rotating mechanical components.
*Hz (Hertz): The hertz (Hz) is the SI unit of electrical frequency, representing the number of alternating current cycles generated or supplied per second to operate the motor.
*A (Ampere): The ampere (A) is the standard unit for measuring electrical current, describing the rate at which electric charge flows through an electrical circuit. In general usage, it is commonly shortened to “amp”.
*kW (Kilowatt): The kilowatt (kW) is a unit of power used to express electrical consumption or motor output capacity. One kilowatt is equal to 1,000 watts and is commonly used to specify the rated power of electric motors and pumping equipment.
Materials of Construction
| Materials of construction | |
| Part | Material |
| Casing | 304 stainless steel |
| Impellers | 304 stainless steel |
| Stages (casing) | 304 stainless steel |
| Pump shaft | 316L stainless steel |
| Stage centring device | 304 stainless steel |
Mechanical seal:
| Carbon Ceramic 316 stainless steel EPDM |
| O-ring | EPDM |
| Plug | 316L stainless steel |
| Motor shell & lantern bracket | Aluminium with baked polyester powder coat finish |
| Motor feet | Xenoy |
| Fan cowl / rear foot (models up to 1.05kW) | Polypropylene |
Horizontal Multistage Pump's Q-H Curve For HM160 & HM270
Included In The Box
Horizontal Multistage Water Pump – HM270-25P
Pressure Switch
User Manual
Proof of Purchase
24 Months of Manufacturer Warranty (Increased by Another 6 Months with e-Warranty Scheme)
Downloads
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