Allweiler NB25-160U3 Centrifugal Pump with ABB Motor

Allweiler GmbH NB25-160U3 1D-W135-19/200 Centrifugal Water Pump with ABB Motor

The Allweiler NB25-160U3 1D-W135-19/200 is a single-stage volute casing block-type centrifugal pump engineered for heavy-duty marine auxiliary duties, central cooling, and industrial liquid circulation. Coupled directly to a premium marine-rated ABB 3-phase squirrel-cage induction motor (Frame 90SLC / 2-pole) via an IEC drive lantern and stub shaft, this unit eliminates external alignment concerns while delivering steady hydraulic performance under continuous S1 duty cycles.

Manufactured in Germany by Allweiler GmbH (a Circor brand), the NB series features hydraulic dimensions conforming to DIN EN 733. Designed to handle fresh water, sea water, heating circulation, and condensate loops, this unit features a rugged ductile/cast construction, corrosion-resistant impeller, and an uncooled, maintenance-free mechanical seal rated up to 10 bar design pressure.

Model Details

• Pump Manufacturer: Allweiler GmbH (Radolfzell, Germany)
• Full Pump Model Code: NB25-160U3 1D-W135-19/200
• Manufacturer Part Number (MPN): NB25-160U3-W135
• Coupled Motor: ABB 3-Phase Induction Motor (Frame: M3KP 90SLC 2 / M2AA / M3AA 90)
• Hydraulic Rating Size: Nominal Discharge DN 25 / Nominal Impeller 160 mm

Features

1. Compact Block Design: Direct-coupled stub shaft configuration according to IEC standards minimizes vibration, optimizes footprint, and requires no coupling alignment during retrofits.
2. High-Efficiency ABB Drive: Driven by a certified ABB 2.2 kW 2-pole motor wound for dual 50 Hz / 60 Hz marine auxiliary grids with IP55/IP56 environmental protection and Class F insulation (Class B temp rise).
3. Robust Hydraulic Materials: Built with a ductile iron casing (EN-GJS-400-15) and high-grade aluminum bronze (CuAl10Ni) impeller for cavitation resistance and long life in marine fluid loops.
4. Standardized Seal Arrangement: Outfitted with an unbalanced, maintenance-free mechanical seal (U3.1D / DIN EN 12756 Shape U) with internal circulation for maximum service longevity.
5. Standard Flange Geometry: Suction DN 40 and discharge DN 25 rated to EN 1092-2 / PN16 with axial suction and radial top discharge configuration.

Technical Details

Compatibility

• Main Marine Diesel Cooling Systems: Compatible as jacket pre-heating circulation and sea chest auxiliary boost for MAN B&W 32/40, 48/60, and 51/60, as well as Wärtsilä 20, 26, and 32 auxiliary generator engines.
• Freshwater Generators & Desalination Units: Alfa Laval (AQUA / JWP series) and Sondex marine evaporators requiring continuous brine/feed pump injection at nominal 1.5–3 m³/h head flows.
• Industrial Chilling Systems: Carrier, Sabroe, and Bitzer marine water-cooled chiller condensers.
• HVAC & Sanitary Modules: Secondary hot water loop booster pumps for passenger vessel and accommodation deck heating matrices.

Part Number & Cross-References

• Pump Direct Code: Allweiler NB 25-160 / NB25-160-U3.1D-W135-19/200
• Impeller Part Number: Allweiler Impeller Ø164mm (Part Ref: 0210.01 / Ident: 550024)
• Mechanical Seal Cross-Reference: Burgmann MG1-24/G6, EagleBurgmann EA560-24, Allweiler Mechanical Seal Kit Material Code
• Coupled Motor Part Code: ABB 3GKP091030-BSH / Type M3KP 90SLC 2 / 3GAA091002-BSE

Applications

• Auxiliary and auxiliary engine fresh water cooling circuits.
• Boiler feed water transfer and high-temperature condensate return lines.
• Marine reverse osmosis (RO) feed circulation and desalination brine discharge.
• Shipboard sanitary, greywater circulation, and deck pre-wash systems.
• Industrial closed-loop HVAC cooling tower water circulation.

Frequently Asked Questions

What does the code NB25-160U3 1D-W135-19/200 stand for?

“NB” represents the Allweiler block-type centrifugal pump design. “25” is the nominal discharge flange diameter in millimeters (DN 25), and “160” refers to the nominal casing impeller diameter (160 mm). “U3.1D” denotes the internal unbalanced mechanical seal type and circulation arrangement, while “W135” indicates the metallurgy combination (ductile iron casing with bronze impeller). “19/200” references the motor shaft fit and lantern flange dimensions.

Can this pump run at both 50 Hz and 60 Hz supply voltages?

Yes. The attached ABB marine motor is wound for dual frequency operation (typically 380–415V @ 50 Hz or 440–480V @ 60 Hz). Note that running at 60 Hz elevates the pump speed from ~2,900 rpm to ~3,485 rpm, which increases both the flow rate and delivery head according to standard centrifugal affinity laws. Verify absorbed power against the 2.2 kW motor rating before swapping to 60 Hz lines.

Is the pump suitable for handling raw seawater?

The W135 material execution features an aluminum bronze (CuAl10Ni) impeller and stainless steel shaft (1.4462), which provides solid corrosion resistance for clean seawater. For heavy silt or open suction raw seawater systems, ensure adequate pre-filtration to prevent abrasive particles from damaging the mechanical seal faces.

How do I troubleshoot abnormal vibration or noise after installation?

First, confirm the direction of rotation matches the arrow on the pump volute (clockwise viewed from motor fan). Second, vent the casing to clear trapped air pockets. If vibration persists, verify that the suction strainer is clean and check for cavitation caused by insufficient suction head. Inspect the DE motor bearing (6205-2Z/C3) for wear or misalignment stresses caused by pipe strain.