4″ Variable speed submersible pumps.


Three-phase, water-filled, permanent magnet synchronous motor with encapsulated resin stator, fully constructed of AISI 304 stainless steel.


Built-in integrated inverter controlled by CM control module.


Multistage pump made of AISI 304 stainless steel.

All the advantages of built-in electronics

An inverter allows 4HS to:

  • Change pump speed to maintain set-pressure regardless of water demand. Consequently

       the pump is operated only when and as needed without wasting energy, thereby

       extending pump life.

  • Starts and stops pump gently, thus reducing peak absorption, mechanical stress.

  • Protects pump and drive from overload, undervoltage, surges, dry running and                                           any abnormal conditions.

Integrated on-board inverter avoids the use of expensive filters and shielded cables reducing electromagnetic emissions to a minimum.

4HS product range meets the needs of commercial and residential markets for water                                         supply, water pressurisation and irrigation.
Compared to conventional solutions, 4HS offers:

  • Energy-saving operation.

  • Quick and simplified application.

  • System reliability.

Construction characteristics and use of specific materials allow 4HS to be suitable for                             drinking water applications.


A ready to use product

4HS range submersible pumps are designed to provide customers with a ready-to-use product, so they are packaged in a kit including:

  • 4HS pump including 2.5 m / 8 ft flat cable lead (ACS-WRAS – KTM compliant)

  • Surface control module (CM)

  • Cable junction kit

  • Pressure transducer 0-16 bar / 0-250 psi

Upon request, Nastec can provide communication and power cables of the desired length.


Centrifugal pump


Built - in inverter module (MINT)



CM: Control Module

CM control module, mounted above-ground, manages the pump operation by changing pump speed to maintain the desired pressure in the system regardless of water demand.

Simply connect the pressure transducer, supplied as standard, and perform a quick set- up of the sensor to configure the pressure range for the system.

During operation, the CM control unit continuously monitors the electrical, hydraulic and thermal parameters providing complete protection against surges, undervoltage, overload and dry running.

4HS cm Nastec.jpg

To set up the system in a constant pressure application

simply install the 4HS pump, connect the CM control module and wire the pressure sensor.

A small pressure tank is normally used to compensate for water loss while the pump is not running.

The control module receives the pressure signal from the pressure transducers and varies pump speed to maintain a constant set pressure regardless of water demand.

In addition to the constant pressure control, CM can also manage the following control modes:

  • fixed frequency

  • constant flow

  • constant temperature

Pump selection

Variable speed allows 4HS to cover a wide range of water flow and heads with just a few models; selecting the proper pump model for an application will help maximise performance and overall efficiency. Use the diagram below to select the most suitable 4HS pump model for your application.


Energy saving

If the water demand decreses, 4HS will reduce the speed (proportional to the frequency) to maintain constant pressure. As you can see from the chart, a speed reduction corresponds a significant decrease of the power consumption. For example, maintaining constant the 6 bar (197 psi), if speed drops from 4800 rpm to 4200 rpm, input power decreases from 1600W to 700W.

Thousand pumps

4HS can be used at a fixed speed by setting the operational frequency. To each frequency curve corresponds a different hydraulic performance and power consumption. This means that each 4HS model covers the performance offered by several standard pumps at fixed speed.


Performance adapting

Among the parameters to be set in the CM control module, particularly useful is the possibility of limiting the maximum current absorbed by the pump. If this threshold is exceeded, for example in the even of a drop in input voltage, the control will reduce the 4HS pump speed to always ensure its operation.