Grundfos Grundfos NB / NBG
Grundfos single-stage close-coupled centrifugal pumps with axial suction: NB to EN 733 and NBG to ISO 2858.
NB and NBG are Grundfos single-stage, non-self-priming centrifugal pumps with a volute casing, axial suction, radial discharge and horizontal shaft, in close-coupled construction: the pump is coupled directly to a standard motor. NB has its main dimensions to EN 733, for general applications, while NBG has its dimensions and nominal performance to ISO 2858 (16 bar; the stainless steel range is designed for PN 25). Both variants are designed to ISO 5199, have flanges to EN 1092-2 and a mechanical seal with dimensions to EN 12756. The NBE and NBGE variants have an MGE motor with integrated frequency converter or a CUE frequency converter mounted on the pump.
The type code shows the connections and the impeller: in NBG 100-65-200/219, “100” is the nominal diameter of the suction port, “65” that of the discharge port, “200” the nominal impeller diameter and “219” the actual impeller diameter, in mm. For a quotation, please send us the full code and the product number from the nameplate; depending on the design and specifications, the lead time on order is usually 1–4 weeks and may be longer.
Models and codes
| Code | Note |
|---|---|
| NB 40-200/206 | NB variant with Grundfos product number 97839223 (design AAF2AESBAQENW1). |
| NB 65-125/137 | NB variant with Grundfos product number 96125040. |
| NB 80-250/270 | NB variant with Grundfos product number 96125146. |
| NB 125-200/209 | NB variant with Grundfos product number 97838088. |
| NB 200-400/296 | NB variant with Grundfos product number 97920843. |
| NBG 100-65-200/219 | Example code from the NBG data booklet: DN 100 suction, DN 65 discharge, 200 mm nominal impeller, 219 mm actual diameter. |
Key specifications
| Construction | monobloc, single-stage, volute casing, non-self-priming; axial suction, radial discharge, horizontal shaft |
|---|---|
| Dimensional standard | NB: EN 733; NBG: ISO 2858 (16 bar; stainless steel range PN 25) |
| Design, flanges, sealing | ISO 5199; EN 1092-2 flanges; EN 12756 mechanical seal (NB and NBG) |
| Flow, NBG/NKG range (50 Hz) | 2 – 2.200 m³/h |
| Head, NBG/NKG range (50 Hz) | 2 – 250 m |
| Liquid temperature (NB and NBG data booklets) | -25…+140 °C; special versions cover -40…+220 °C |
| Variable-speed variants | NBE, NBGE (MGE motor or CUE converter) |
| ATEX design | on request, group II, categories 2G/D and 3G/D (NBG) |
The NB range is part of the current Grundfos offer, and the NBG, NBGE, NKG, NKGE (50 Hz) data booklet is published by Grundfos; some individual variants may be discontinued, and the replacement is determined by product number.
Frequently asked questions
How does NB differ from NBG?
Both are close-coupled single-stage pumps with axial suction. NB has its main dimensions to EN 733, for general applications, while NBG has its dimensions and nominal performance to ISO 2858 (16 bar), for more demanding industrial duties. The variants with a separate motor, connected by a coupling, are NK and NKG.
What data do you need for a replacement NB or NBG pump?
The full code from the nameplate (for example NB 65-125/137 followed by the design code), the Grundfos product number, the pumped liquid and its temperature. If the variant is no longer produced, we look for the replacement indicated by Grundfos for that product number.
Can the pump be dismantled without disconnecting the pipes?
Yes, on NB and NBG the back pull-out construction allows the motor, the motor stool and the impeller to be removed without dismantling the pump casing or the pipes, according to the Grundfos data booklets.
Other Grundfos series
We do not select the operating point on the pump curve and we do not confirm interchangeability with pumps from other series; we confirm the code, the product number and the replacement indicated by Grundfos for discontinued variants.
Updated: 2026-11-12