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SKU: 93209294
Grundfos NB 50-125/135 Cast Iron 5.5 kW End Suction Centrifugal Pump with Closed Impeller
Australia-Wide
(08) 9240 2992
Official Grundfos
Peace of Mind
Product Overview
Commercial fluid circulation duties in hydronic heating plants and industrial process loops are handled by the NB 50-125/135 end-suction centrifugal pump. Equipped with a 5.5 kW motor drive, the unit features standardized DN 65 axial inlet and DN 50 radial outlet flanged pipe connections.
Liquid circulation capacity reaches a rated flow volume of 1264 L/Min while generating 19.13 m maximum head limit. The casing body is cast in EN-GJL-250 iron with electrocoated protective finish. Fluid movement is driven by a stainless steel impeller with BQQE mechanical shaft seal. Net product weight measures 103 kg.
A 5.5 kW drive motor powers the NB 50-125/135 unit from a 415 V three-phase electrical source, drawing 10.5 Amps nominal current. Working fluid limits handle liquid temperatures from -25°C to 120°C under line pressure ratings up to 16 bar. Standard DN 65 inlet and DN 50 outlet flanged connections support mounting.
Protective features on the NB 50-125/135 pump include an IP55 motor enclosure, Class F winding insulation, and internal PTC thermistor monitoring. The back-pull-out design allows complete drive and impeller extraction without disturbing connected suction or discharge pipework flanges in plant rooms.
Features
- Integrally cast suction and discharge ports with dedicated vent and drain ports provide direct connection points without additional fittings.
- No baseplate or grouting required to maintain correct shaft alignment and vibration levels within Hydraulic Institute standards.
- Cataphoretic electrocoating on cast iron internal surfaces provides barrier protection against oxidative corrosion in hydronic circulation loops.
- Close-coupled configuration eliminates coupling alignment procedures and reduces overall installation footprint compared to long-coupled alternatives.
- Ball bearing support arrangement accommodates both radial and axial thrust loads generated during continuous duty operation at rated speed.
- PN16 flanged connection ratings on sizes up to and including DN 150 provide elevated working pressure capability beyond standard EN733 10 bar ratings.
- O-ring seal between pump housing and cover eliminates leakage risk at the volute-to-cover joint under sustained operating pressures.
IMPORTANT:Bulk freight charges apply. Please contact us for a freight quote before ordering.
SPECIFICATIONS
| Max Flow | 1264 L/Min |
| Max Head | 19.13 m |
| Power | 5.5 kW / 415v |
| Rated Current | 10.5 Amps |
| Suitable For | Commercial HVAC Hydronic Circulation |
| Body Material | Cast Iron |
| Liquid Temperature | '-25°C to 120°C |
| Inlet Size | 65 mm |
| Outlet Size | 50 mm |
| Warranty | 24 Months |
Warranty & Returns
All products supplied by Foundation Pumps are covered by a minimum 12-month warranty unless otherwise stated. Some brands may offer longer manufacturer warranties. Warranty covers manufacturing defects, faulty materials and workmanship under normal use.
- Products must be installed correctly and in accordance with the manufacturer’s instructions.
- Warranty does not cover incorrect installation, misuse, dry running, normal wear and tear, unauthorised repairs or damage caused by external factors.
- Proof of purchase, photos, videos and installation details may be requested when assessing a warranty claim.
- The customer is responsible for returning the product to Foundation Pumps or the nominated service centre unless otherwise agreed.
- Removal, reinstallation, labour and associated site costs are generally the customer’s responsibility unless required under Australian Consumer Law.
- Change-of-mind returns may be accepted within 30 days provided the product is unused, uninstalled and returned in its original packaging.
- Customers are responsible for return freight costs for change-of-mind returns.
- Restocking fees may apply to special-order, bulky or non-stocked products.
- Used, installed or specially ordered products may not be eligible for change-of-mind returns.
- If a product arrives damaged or faulty, please contact Foundation Pumps as soon as possible so we can assist with the appropriate repair, replacement or refund.
Your rights under Australian Consumer Law are not affected.
Within high-head commercial plant rooms, what maximum vertical discharge column is achieved?
Foot-supported volute engineering allows Grundfos NB 50-125/135 to sustain a peak dynamic head of approximately 19.13 m.
With generous volute internal dimensions, what maximum fluid circulation volume is delivered on site?
Within centralized institutional facilities, NB 50-125/135 circulates a peak volumetric flow of approximately 1264 L/Min.
How do the electrocoated volute and balanced closed impeller maintain long-term physical integrity?
The end-suction hydraulic chamber in NB-50-125-135 integrates an EN-GJL-250 cast iron volute with a durable stainless steel impeller.
Under sustained heavy pumping duty, what motor kilowatts, line voltage, and amps are required on site?
Electrical specifications for NB 50 125 135 indicate a 5.5 kW drive running on a three-phase 415 V connection drawing 10.5 Amps.
Regarding media conditions, what minimum and maximum fluid temperatures can this end-suction pump sustain?
Media circulating through NB/50/125/135 can range from -25°C to 120°C under maximum permissible working pressures of 10 bar.
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