In this module, we’ll explore the Grundfos NB, NBS, NK end suction series and their performance characteristics. Let’s get started.

At Grundfos, the three types of end suction pumps (close-coupled, split-coupled, and long-coupled) are further organised into two main categories:

BLOC, which includes close- and split-coupled designs

NORM, which covers long-coupled designs

So what do BLOC and NORM mean?

BLOC pumps, such as the NB/NBG and NBS, are compact, modular units that are easy to install and suitable for a wide range of applications.

The NBS supports slightly larger discharge sizes and higher motor ratings than the NB.

NORM pumps, such as the NK/NKG, offer more flexibility for servicing, support higher-power motors, and are suited for heavy-duty applications.

Whether BLOC or NORM, the NB, NBS, NK range is built to strict international standards for safety and performance: ISO 5199 for general design criteria, including running clearances, shaft and bearing design, and test specifications:

ASME flange standards for compatibility with global piping systems

EN 733 for general utility/water applications or ISO 2858 for heavy-duty industrial use.

EN 733 designs are ideal for standard, utility, and general industrial applications… while ISO 2858 pumps handle higher pressures and more demanding industrial duties.

These standards ensure reliability, global compatibility, and safe operation under expected conditions.

Now let’s take a closer look at the Grundfos NB, NBS, NK range. The NB (close-coupled) and NK (long-coupled) pumps are available in a variety of materials, configurations, and motor options. Depending on the model, capacities reach up to 5,800 gallons per minute, or 1,300 cubic metres per hour, with heads of around 450 feet, or 137 metres. Discharge sizes range from 1.25 to 10 inches, … and selected models feature double-volute designs to balance radial forces, reducing vibration and wear.

Smaller pumps use a centreline discharge to ensure a self-venting design and enable more compact piping layouts, … while larger pumps feature a tangential discharge to prevent the overall pump height from becoming too tall.

A major advantage of Grundfos end suction pumps is the availability of E-variants, which integrate advanced motor and drive technology. These pumps use Permanent Magnet Synchronous Motors, known as PMSMs, which is the same technology found in modern electric vehicles.

PMSMs rotate in perfect synchrony with the magnetic field, eliminating slip losses and increasing efficiency.

The benefits of the PMSMs include:

IE5 efficiency, two levels above NEMA Premium

Lower energy consumption

Quieter operation

Improved performance at partial load

Paired with a variable frequency drive (VFD), the PSMS adjusts its speed automatically to system demand, reducing energy use by up to 30-40 percent compared with constant-speed operation using an asynchronous motor.

In Grundfos end suction pumps, these motors are implemented as Grundfos MLE or MGE motors, which integrate smart controls and connectivity directly into the pump.

These motors offer several key features:

Built-in PI controller and programmable inputs and outputs

Standard Modbus RTU communication, with optional CIM for Ethernet/IP, BACnet, Profibus, or Profinet

Bluetooth connectivity for quick access via Grundfos digital tools

These features make the Grundfos end suction pump range highly efficient, precise, and easy to integrate into modern connected systems.

The Grundfos end suction pump range combines proven design with advanced motor technology, offering flexible solutions for a wide range of industrial and utility applications.

In the next module, we’ll look at the application-focused configurations of Grundfos end suction pumps.