Grundfos MAGNA1 25-100 N Variable Speed Pump 240V Stainless Steel 99221226 #4307

Grundfos MAGNA1 25-100 N – Stainless Steel Variable-Speed Hot Water Circulator Pump (99221226) #4307

This listing is for a Grundfos MAGNA1 25-100 N high-efficiency, single-head, variable-speed circulator pump featuring a stainless steel pump housing, G 1 1/2" threaded connections and a 180 mm port-to-port installation length.

The MAGNA1 N range is designed for efficient water circulation in domestic hot-water systems, commercial heating installations, cooling circuits and other suitable building-services applications.

Unlike standard cast-iron MAGNA1 pumps, the N version features a stainless steel housing, making it particularly suitable for domestic hot-water circulation and applications requiring improved corrosion resistance.

The pump incorporates a high-efficiency permanent-magnet motor and integrated electronic speed control. Its proportional-pressure, constant-pressure and constant-curve operating modes allow performance to be selected according to the hydraulic requirements of the installation.

The MAGNA1 provides straightforward operation and energy-efficient circulation without the more advanced monitoring and control features found on the MAGNA3 range.

Condition: Supplied as new/unused surplus stock. The pump has not been installed or used but may show minor cosmetic marks from storage and handling.

Guarantee: Supplied with our 2-year guarantee.

Technical Specifications

• Manufacturer: Grundfos
• Product range: MAGNA1
• Model: MAGNA1 25-100 N
• Grundfos product number: 99221226
• EAN: 5712608941993
• Model generation: Model C
• Pump configuration: Single-head circulator
• Pump design: Canned-rotor wet-rotor circulator
• Pump housing: Stainless steel
• Housing material specification: EN 1.4308 / ASTM 351 CF8
• Impeller material: PES reinforced with 30% glass fibre
• Nominal connection size: DN25
• Pipe connection: G 1 1/2" threaded
• Connection pressure rating: PN10
• Port-to-port installation length: 180 mm
• Electrical supply: Single-phase 230V AC
• Supply frequency: 50/60 Hz
• Motor type: Permanent-magnet synchronous motor
• Speed control: Integrated electronic frequency converter
• Electrical power input (P1): 9–176 W
• Maximum current consumption: 1.42 A
• Maximum head: 10 m (approximately 0.98 bar differential pressure)
• Maximum flow: Approximately 9.4 m³/h (2.61 L/s), towards the low-head end of the performance curve
• Maximum operating pressure: 10 bar
• Liquid temperature range: -10°C to +110°C
• Ambient temperature range: 0°C to +40°C
• Enclosure protection: IPX4D
• Insulation class: F
• Temperature class: TF110
• Energy Efficiency Index: EEI 0.20
• Net weight: Approximately 4.38 kg
• Manufacturer gross weight: Approximately 4.78 kg
• Control: Integrated variable-speed electronic controller
• Remote monitoring: Fault relay output
• Remote operation: Digital start/stop input
• Communication: Grundfos GO Remote via compatible infrared communication equipment
• Stock reference: #4307

Important hydraulic performance information: The maximum head of approximately 10 metres and maximum flow of approximately 9.4 m³/h represent different points on the pump performance envelope.

Maximum head occurs towards the low-flow end of the curve. Maximum flow occurs at significantly lower differential head. These maximum values cannot be achieved simultaneously.

Always consult the manufacturer performance curve to confirm that the required flow and head can be achieved together.

Need help confirming suitability?
Call us on 01803 220416 for technical advice.

Manufacturer Product Information

For full manufacturer specifications, performance information and technical documentation, please visit:

View Grundfos MAGNA1 25-100 N (99221226) – Official Product Information

Technical Documentation

The following Grundfos-generated technical datasheet contains the manufacturer's specifications, performance curves, electrical data, dimensions and material information for product number 99221226.

Download Grundfos MAGNA1 25-100 N – Technical Datasheet (PDF)

Typical Applications

The Grundfos MAGNA1 25-100 N is intended for circulation of suitable clean liquids in heating, hot-water and building-services installations.

• Domestic hot-water circulation and secondary-return systems
• Commercial domestic hot-water distribution systems
• Hotels, schools and commercial buildings
• Hot-water circulation in suitable healthcare and institutional buildings
• Commercial central-heating systems
• Radiator heating circuits
• Underfloor heating systems
• Boiler circulation and mixing loops
• Heating system distribution circuits
• Ground-source heat pump systems
• Suitable solar-heating circulation circuits
• Air-conditioning and chilled-water systems
• Small commercial cooling installations
• Replacement of compatible threaded circulation pumps

Stainless steel housing advantage: The stainless steel N variant offers improved corrosion resistance compared with standard cast-iron circulators.

This makes it suitable for consideration in domestic hot-water circulation systems where a stainless steel pump housing is required.

Final suitability depends on the liquid properties, system design, operating temperatures and applicable water regulations.

MAGNA1 Control Functions

The MAGNA1 incorporates an electronic controller and high-efficiency permanent-magnet motor.

The pump can be configured using its integrated operating panel, allowing the appropriate control setting to be selected for the installation.

Proportional-Pressure Control

Proportional-pressure control adjusts the pump's differential-pressure setting according to the flow demand within the selected control curve.

This is particularly useful for heating systems where thermostatic radiator valves or other control valves alter the system resistance.

The pump provides three proportional-pressure settings:

• PP1: Low proportional-pressure curve
• PP2: Medium proportional-pressure curve
• PP3: High proportional-pressure curve

Constant-Pressure Control

Constant-pressure control aims to maintain a selected differential pressure as system flow requirements change, within the available pump performance range.

Three settings are available:

• CP1: Low constant-pressure setting
• CP2: Medium constant-pressure setting
• CP3: High constant-pressure setting

This operating mode may be suitable for underfloor heating and other circulation systems requiring a relatively constant differential pressure.

Constant-Curve Operation

The pump can also operate at one of three constant-speed curve settings.

• I: Low constant-speed curve
• II: Medium constant-speed curve
• III: High constant-speed curve

Constant-curve operation can be useful when replacing older fixed-speed circulators, provided the selected curve matches the required operating duty.

External Control and Monitoring

The MAGNA1 Model C includes basic external control and monitoring functionality.

• Digital input: External start/stop control
• Relay output: Fault or alarm indication
• Grundfos GO Remote: Supported through compatible infrared communication equipment
• Integrated operating panel: Local selection of pump operating modes

The single-head MAGNA1 does not provide the same advanced building-management communication options as the MAGNA3.

For applications requiring advanced BMS integration, flow monitoring, energy monitoring or more sophisticated control functions, a suitable MAGNA3 model may be more appropriate.

Frequently Asked Questions

What does MAGNA1 25-100 N mean?

• MAGNA1: Grundfos high-efficiency electronically controlled circulator range.
• 25: Nominal DN25 connection size.
• 100: Maximum head class of approximately 10 metres.
• N: Stainless steel pump housing.
• 180: Port-to-port installation length of 180 mm.

The Grundfos manufacturer product number for this particular pump is 99221226.

What does the N mean on a Grundfos MAGNA1?

The N designation identifies a stainless steel pump housing.

Standard MAGNA1 circulators generally feature cast-iron pump housings, whereas the N versions use stainless steel for applications where different corrosion-resistance or water-quality requirements apply.

For this model, the housing material is stainless steel EN 1.4308 / ASTM 351 CF8.

Is the MAGNA1 25-100 N suitable for domestic hot water?

Yes, subject to the installation requirements.

The stainless steel MAGNA1 N range is designed for applications including domestic hot-water circulation and secondary-return systems.

The stainless steel housing makes it more suitable for these applications than a standard cast-iron circulator.

The installation must comply with applicable water regulations, temperature requirements and manufacturer guidance.

Is the MAGNA1 N suitable for potable-water applications?

The stainless steel MAGNA1 N range is intended for suitable domestic hot-water circulation applications.

Grundfos has included MAGNA1 N products in its UK catalogues of WRAS-approved circulators.

However, approval status and installation requirements should be verified for the exact product and application before installation.

A stainless steel housing alone does not establish compliance with every drinking-water regulation.

What is the difference between MAGNA1 N and a standard MAGNA1?

The main difference is the pump housing material.

• MAGNA1: Standard cast-iron housing for suitable heating and closed-loop circulation applications.
• MAGNA1 N: Stainless steel housing for suitable domestic hot-water circulation and other applications requiring improved corrosion resistance.

Both versions use high-efficiency electronic speed control.

The stainless steel N version should be selected where the pumped liquid or application requires this housing material.

What is the difference between MAGNA1 and MAGNA3?

Both MAGNA1 and MAGNA3 are high-efficiency electronically controlled circulation pumps.

MAGNA1 provides straightforward operation with proportional-pressure, constant-pressure and constant-speed control settings.

It also includes basic fault monitoring and external start/stop control.

MAGNA3 provides more advanced control and monitoring functions, including:

• AUTOADAPT
• FLOWADAPT
• FLOWLIMIT
• Additional control modes
• Integrated flow estimation
• Advanced operating information
• Energy monitoring functionality
• Expanded external control and communication options
• Optional BMS communication through compatible modules

For straightforward circulation duties, MAGNA1 is often the more economical solution.

Where advanced monitoring, integrated system control or BMS communication is required, MAGNA3 may be more appropriate.

What is the maximum head of this pump?

The maximum head class of the MAGNA1 25-100 N is 10 metres.

This is approximately equivalent to 0.98 bar differential pressure when pumping water.

The maximum head occurs towards the low-flow end of the pump performance curve.

This figure must not be confused with the maximum system operating pressure of 10 bar.

What is the maximum flow rate?

The upper flow range shown by the manufacturer performance curve is approximately 9.4 m³/h.

This is equivalent to approximately:

• 2.61 litres per second
• 157 litres per minute

This upper flow value occurs at reduced differential head.

The available flow reduces as the required head increases.

Always check the manufacturer's performance curve against the required operating duty point.

Can this pump increase water pressure?

The MAGNA1 is a circulator designed to move water through a suitable hydraulic circuit.

It develops differential pressure to overcome resistance in pipework, valves and connected equipment.

It is not designed as a direct replacement for a dedicated domestic mains-water pressure booster.

For boosting mains-water pressure, a suitable booster pump or pressure-boosting system should be selected instead.

What electrical supply is required?

The MAGNA1 25-100 N operates from a single-phase 230V AC supply.

The MAGNA1 Model C range supports 50/60 Hz electrical supplies.

The manufacturer's specified electrical input power for product 99221226 is 9–176 W.

Maximum current consumption is approximately 1.42 A.

Does the MAGNA1 require an external inverter or VFD?

No.

The MAGNA1 contains an integrated electronic frequency converter and permanent-magnet motor.

Pump performance is adjusted through the integrated electronic controller.

A separate external variable-frequency drive is not required.

Can this pump automatically vary its speed?

Yes.

When operating in proportional-pressure or constant-pressure control mode, the pump adjusts its speed to maintain the selected control characteristic as system demand changes.

In constant-curve mode, the pump follows the selected fixed-speed characteristic.

The MAGNA1 does not include the advanced AUTOADAPT function found on MAGNA3 pumps.

Does the MAGNA1 support Grundfos GO Remote?

Yes.

This MAGNA1 Model C supports communication with Grundfos GO Remote using compatible infrared communication equipment.

The single-head MAGNA1 communicates via infrared rather than the radio communication used by certain other Grundfos pumps.

A compatible Grundfos interface is required; a smartphone alone should not be assumed to provide direct communication.

Grundfos GO Remote can provide supported commissioning and diagnostic functions, including alarm information and adjustment of certain settings.

Can this pump be controlled by a building management system?

The MAGNA1 provides basic external control and monitoring through its digital start/stop input and fault relay output.

These connections can be incorporated into a suitable external control system.

However, MAGNA1 does not provide the same advanced BMS communication capabilities as the MAGNA3 range.

Where BACnet, Modbus or more advanced building-management integration is required, a compatible MAGNA3 or another suitable circulator should be considered.

Does this MAGNA1 have a 0–10V input or PWM control?

This MAGNA1 Model C is intended for operation using its integrated control modes and supported external start/stop input.

It should not be assumed to support external 0–10V speed control or dedicated PWM speed-control signals.

If the existing installation requires an analogue speed-control signal or PWM interface, the replacement pump's control compatibility must be checked before ordering.

Can this pump replace Grundfos 98254908?

Grundfos product number 98254908 identifies an earlier MAGNA1 25-100 N stainless steel circulator variant.

Product number 99221226 identifies the later MAGNA1 25-100 N Model C version.

Both belong to the same nominal DN25, 10-metre head class and 180 mm installation-length category.

However, differences between generations may affect electrical connections, controls and installation requirements.

The complete manufacturer specifications should be compared before treating the two versions as interchangeable.

Can this pump replace an older Grundfos UPS circulator?

Potentially, provided the hydraulic duty, connection dimensions, electrical supply and installation requirements are compatible.

The MAGNA1 uses a high-efficiency permanent-magnet motor and electronically controlled operation.

It may offer an energy-efficient alternative to certain older fixed-speed circulators.

However, not every UPS pump is directly interchangeable with this model.

The existing pump's flow, head, connection dimensions and operating requirements must be checked.

Can this pump replace a Wilo or Lowara circulator?

Potentially.

The MAGNA1 25-100 N may be considered as an alternative to compatible circulators from other manufacturers.

However, matching the nominal connection size and installation length alone does not establish hydraulic equivalence.

Always compare:

• Required operating flow
• Required operating head
• Complete pump performance curve
• Connection dimensions
• Installation length
• Electrical supply
• Required control functions
• Pump housing material

Can this pump be used with glycol?

MAGNA1 pumps can be used with suitable water/glycol mixtures within the manufacturer's permitted operating limits.

Grundfos provides guidance for mixtures containing up to approximately 50% glycol, subject to liquid viscosity and other operating restrictions.

Glycol mixtures have different viscosity and density characteristics from water and may reduce available hydraulic performance.

The concentration, temperature and chemical compatibility must be checked before installation.

What liquids are unsuitable for this pump?

The MAGNA1 is intended for suitable clean, thin, non-aggressive liquids without solids or fibres.

It should not be used for:

• Wastewater or sewage
• Liquids containing abrasive particles
• Liquids containing significant suspended solids
• Flammable or explosive liquids
• Petrol or diesel
• Sea water
• Strong acids or aggressive chemicals
• Liquids outside the manufacturer's permitted temperature or viscosity limits

The stainless steel housing does not make the pump suitable for every corrosive liquid or chemical application.

What minimum inlet pressure is required?

The minimum required inlet pressure depends on the liquid temperature.

Grundfos MAGNA1 Model C guidance for the 25-100 size gives the following minimum relative inlet pressures:

• 75°C: 0.10 bar
• 95°C: 0.35 bar
• 110°C: 1.00 bar

Adequate inlet pressure is necessary to reduce the risk of cavitation and damage to the pump bearings.

Additional installation considerations may apply at higher altitudes or under unusual operating conditions.

Does this pump have a mechanical shaft seal?

No.

The MAGNA1 uses a canned-rotor wet-rotor construction.

There is no conventional mechanical shaft seal between the motor and pump.

The pumped liquid lubricates the rotor bearing arrangement.

This reduces routine maintenance requirements compared with conventional mechanically sealed circulation pumps.

Does the pump require external motor protection?

The MAGNA1 includes integrated electronic motor protection.

Separate conventional motor overload protection is not normally required.

However, the electrical installation must include the appropriate supply protection, isolation and other protective arrangements specified by Grundfos and applicable regulations.

Can the pump be installed in vertical or horizontal pipework?

Yes, subject to the manufacturer's installation requirements.

The pump may be installed in suitable horizontal or vertical pipework, but the motor shaft must remain horizontal.

The control unit orientation and installation clearances must also comply with the relevant instructions.

Are threaded unions supplied?

The pump features G 1 1/2" threaded connections.

Unless specifically shown or stated as included, mating unions, gaskets and other installation accessories should not be assumed to form part of the supply.

Please refer to the product photographs or contact us to confirm the accessories included.

Is this a new pump?

This unit is supplied as new/unused surplus stock.

It has not been installed or used, but minor cosmetic marks may be present from storage or handling.

The pump is inspected prior to dispatch and supplied with our 2-year guarantee.

Replacement and Selection Guidance

Before purchasing the MAGNA1 25-100 N as a replacement circulator, we recommend checking:

• Existing pump manufacturer and model
• Existing manufacturer product number
• Required flow rate in m³/h or L/s
• Required operating head in metres or bar
• Threaded connection dimensions
• Port-to-port installation length
• Electrical supply requirements
• Control and monitoring connections
• Required operating mode
• Liquid type and temperature
• Maximum system pressure
• Required pump housing material

The MAGNA1 provides adjustable pump performance within its available hydraulic envelope.

However, the required operating duty must fall within the manufacturer's performance curve.

The correct control setting should be selected during commissioning according to the requirements of the system.

For assistance comparing this pump with an existing Grundfos, Wilo, Lowara or other circulator, please contact us with the existing pump model and required flow and head.

About Our Stock

Stock reference: #4307

We specialise in supplying quality new and unused surplus pumps, circulators and industrial equipment.

This unit is inspected prior to dispatch and supplied with our 2-year guarantee.

Technical information and selection guidance: Specifications are provided in good faith using available manufacturer documentation.

Performance figures, application descriptions and FAQ content are intended to assist with product identification and preliminary selection.

Actual operating performance depends on system resistance, pipework configuration, liquid characteristics, control settings and installation conditions.

Please consult the relevant Grundfos documentation and confirm suitability for your application before purchasing or installing this equipment.