Circulator pump GRUNDFOS Magna3 25-100 – inline circulation pump for heating systems, model 97924247

GRUNDFOS Magna3 25-100 is an inline circulator pump engineered for circulation of heating water and domestic hot-water recirculation. Intended for central heating systems, radiator loops and hot-water return circuits, the pump combines a compact housing with electronically controlled speed control to maintain stable flow and temperature. The design supports straightforward integration into standard pipe runs and provides automatic regulation of hydraulic performance to match system demand.

Advantages

The pump offers electronically modulated speed control that adapts to changing load conditions, reducing energy consumption compared with fixed-speed units. Its compact inline construction allows installation in tight spaces and easy replacement of many conventional circulators. Built-in protection and intelligent control functions improve system stability and help prevent overheating and unnecessary pump operation. Materials and sealing suitable for heating system water ensure long-term, reliable operation.

Suitable for

• Central heating systems in residential and light commercial buildings
• Radiator circuits and underfloor heating where inline installation is required
• Domestic hot-water recirculation loops to maintain setpoint temperatures
• Replacement of existing inline circulators with similar hydraulic characteristics

Key specifications

• Type: Inline circulator pump for heating and hot-water recirculation
• Hydraulic range: designed for medium head and flow typical of domestic and light commercial heating circuits
• Control: electronically controlled variable speed with multiple operating modes for energy-optimised performance
• Connection: standard pipe connection dimensions for direct inline mounting
• Housing: compact construction suitable for confined installation spaces
• Fluid compatibility: formulated for heating system water and glycol-mixed heating fluids within standard concentration limits
• Protection: integrated control functions to prevent dry running and reduce wear during low-load conditions

How to use

Install the GRUNDFOS Magna3 25-100 inline in the return or feed line according to system design and local regulations, ensuring correct flow direction and secure mechanical connections. Connect electrical supply and control wiring following the manufacturer’s wiring diagram and observe grounding requirements. Configure the pump control mode to match system type (constant pressure, proportional pressure, or fixed curve) and set any required parameters for temperature and flow. Commission the system by purging air from the circuit, verifying flow, and monitoring temperature stability under different operating conditions.

Usage recommendations

For reliable operation, use corrosion-inhibited water or manufacturer-recommended glycol mixtures, maintain filtration to prevent particulate ingress, and schedule periodic inspection of electrical connections and pump seals. When replacing an existing unit, match hydraulic characteristics and check mounting orientation to ensure system compatibility.