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Grundfos MAGNA Commercial Circulator Pumps

Intelligent Circulation for Commercial Heating & Cooling

Grundfos MAGNA circulator pumps move water through commercial heating, cooling and air-conditioning systems. MAGNA1 covers straightforward circulation with simple controls. MAGNA3 adds automatic adaptation, built-in sensing, heat energy monitoring and building management system (BMS) connectivity.

Tricel supplies both ranges for new installations, refurbishment projects and pump replacement. We can help you select the right model from your flow, head, application and control requirements.

Meet the Grundfos MAGNA Range

Grundfos MAGNA circulator pumps are designed for heating and cooling in commercial buildings. There are six models: MAGNA1 and MAGNA3, each available as a single-head pump, a twin-head pump (D) and a stainless-steel pump (N). All are wet-rotor pumps with no shaft seal, which Grundfos describes as maintenance-free.

MAGNA1

Single-head

Grundfos MAGNA1

CONTROL
Preset settings

PUMP HEADS
Single

HOUSING
Cast iron

BEST FOR
Simple systems & replacement

For heating and cooling systems where dependable circulation and simple control are the priority. Grundfos positions MAGNA1 as a lower-cost option for replacing older circulators in commercial buildings.

Twin-head

Grundfos MAGNA1 D

CONTROL
Preset settings

PUMP HEADS
Twin: alternating

HOUSING
Cast iron

BEST FOR
Systems that need a standby head

Two pump heads in one housing, connected wirelessly. The heads alternate on a time basis so that operating hours are shared, and if one head becomes unavailable the other takes over.

Stainless steel

Grundfos MAGNA1 N

CONTROL
Preset settings

PUMP HEADS
Single

HOUSING
Stainless steel

BEST FOR
Domestic hot water

The stainless-steel version of MAGNA1, for applications where the liquid requires it. Grundfos strongly recommends stainless-steel pumps for domestic hot-water applications to avoid corrosion.

MAGNA3

Single-head

Grundfos MAGNA3

CONTROL
Automatic adjustment

PUMP HEADS
Single

HOUSING
Cast iron

BEST FOR
Variable-flow & BMS systems

Grundfos’s premium circulator, for systems where control and monitoring matter. A built-in differential-pressure and temperature sensor lets the pump adjust itself to demand; in its factory setting, AUTOADAPT, Grundfos states that no manual adjustment is needed in 80% of installations.

Twin-head

Grundfos MAGNA3 D

CONTROL
Automatic adjustment

PUMP HEADS
Twin: alternating

HOUSING
Cast iron

BEST FOR
Critical & high-demand systems

Two MAGNA3 pump heads in one housing, communicating wirelessly. In cascade mode both heads can run together to meet higher demand; in backup mode one head stands by. Grundfos recommends it for buildings where downtime is not tolerated, such as hospitals.

Stainless steel

Grundfos MAGNA3 N

CONTROL
Automatic adjustment

PUMP HEADS
Single

HOUSING
Stainless steel

BEST FOR
Domestic hot water & drinking water

All the features of MAGNA3 in a stainless-steel housing, for applications where the liquid requires it, such as domestic hot water. Grundfos states that MAGNA3 N is suitable for pumping drinking water.

MAGNA1 vs MAGNA3: Which Do You Need?

Feature	MAGNA1	MAGNA3
Best suited to	Straightforward commercial circulation and replacing older circulators	Systems that need automatic adaptation, monitoring or BMS integration
Control settings	Nine presets: 3 proportional-pressure, 3 constant-pressure, 3 constant-curve	Proportional pressure, constant pressure, constant temperature, differential temperature, constant curve
AUTOADAPT	-	Yes (factory setting)
FLOWADAPT / FLOWLIMIT	-	Yes
Built-in differential-pressure and temperature sensor	-	Yes
Heat energy monitoring	-	Yes
Set-up	Single button, light fields and Grundfos Eye status indicator	Colour display and Grundfos GO app
Grundfos GO app	Yes	Yes
External control and monitoring	Fault relay output and digital start/stop input	Digital and analogue inputs, relay outputs, optional CIM fieldbus modules
Twin-head (D) versions	Yes: alternating, with standby	Yes: alternating, backup or cascade
Stainless-steel (N) versions	Yes	Yes
Energy Efficiency Index (EEI)	≤ 0.20 single-head; ≤ 0.23 twin-head	≤ 0.18

Choose MAGNA1

where you need a dependable commercial circulator with straightforward control.

Choose MAGNA3

where the system will benefit from automatic adaptation, flow limiting, energy monitoring or BMS integration.

MAGNA3 Pump Control

How MAGNA3 Controls Itself

Rather than running at one fixed output, MAGNA circulators change speed as system demand changes. This matters in commercial heating and cooling, where valves open and close and the required flow varies through the day.

AUTOADAPT

The pump continuously adjusts its control curve to the system’s actual characteristics. Grundfos states that this keeps energy consumption and valve noise to a minimum. It is also useful in replacement work where the original duty point is not known.

FLOWADAPT

FLOWADAPT combines AUTOADAPT with FLOWLIMIT. The pump adapts to demand but never exceeds a set maximum flow, which Grundfos says can save the cost of a separate pump throttling valve.

Variable-Speed Operation

Pump output follows the system’s demand instead of running continuously at maximum.

Heat Energy Monitoring

MAGNA3 calculates heat energy distribution and consumption from its own measurements, which can help identify imbalances in the system without a separate energy meter.

Twin-Head and Stainless-Steel Versions

D and N are versions within the MAGNA1 and MAGNA3 ranges, not separate products. The letters appear in the model name.

MAGNA D Twin-Head Pumps

Standby Capacity for Critical Systems

The D in a MAGNA model name means twin-head: two pump heads share one pump housing. If one head becomes unavailable, the other takes over, and the heads alternate so that operating hours are shared between them.

MAGNA3 D offers three twin-head modes: alternating, backup and cascade, in which both heads can run together to meet higher demand. Grundfos recommends twin-head pumps where downtime is not acceptable, such as in hospitals.

MAGNA N Stainless-Steel Pumps

Housing Matched to the Liquid

The N in a MAGNA model name means a stainless-steel pump housing. Standard versions use cast iron.

Grundfos strongly recommends stainless-steel pumps for domestic hot-water applications to avoid corrosion, and states that MAGNA3 N is suitable for pumping drinking water. Housing material should always be matched to the liquid being pumped.

Monitoring and BMS Connectivity

MAGNA3 can be set up and checked with the Grundfos GO app: adjust settings, view operating data, check warnings and alarms, and generate reports.

Optional Grundfos CIM (Communication Interface Module) modules connect MAGNA3 to building management systems over standard fieldbus protocols.

BACnet

Modbus

LonWorks

PROFIBUS

GENIbus

GSM/GPRS

Ethernet

MAGNA1: Simple System Connection

MAGNA1 connects to simpler control systems through its fault relay output and digital start/stop input. For example, a controller can stop a boiler from starting if the pump reports a fault.

Commercial Applications for Grundfos MAGNA

Commercial Heating

Circulation for variable-flow and conventional hydronic heating systems.

Cooling & Chilled Water

Water circulation for cooling and air-conditioning systems.

Primary & Secondary Circuits

Pump options for different parts of a commercial HVAC distribution system.

Commercial Plant Rooms

Compact circulators for new plant, system upgrades and replacements.

Refurbishment Projects

MAGNA1 is a practical option when replacing older circulators in existing systems.

Critical Building Services

Twin-head MAGNA pumps provide standby capacity where heating or cooling must keep running.

Choosing the Right MAGNA Pump

Pump selection starts with the system. Choosing between MAGNA1 and MAGNA3 is only the first step; the pump also needs to match the hydraulic requirements of the installation. These are the main factors our team will ask about.

Factor	What we need to know
Flow rate	The volume of water that must circulate through the system.
Head	The resistance the pump needs to overcome.
Heating or cooling	Different circuits have different operating requirements.
Constant or variable flow	This determines how much benefit advanced control can provide.
Single or twin-head	Critical systems may need standby capacity.
Control requirements	From simple start/stop to full BMS integration.
Existing pump details	For replacements, the current pump, duty and connections.

Replacing an Existing Circulator?

If you are replacing a Grundfos MAGNA, an older Grundfos UPS or another commercial circulator, send us the pump model, nameplate details and system duty where available. Some replacements fit the existing pipework directly; others need a spacer kit or have a different flange size. We check this before recommending a pump.

Why Choose Grundfos MAGNA?

Measured Energy Performance

MAGNA3 has an Energy Efficiency Index (EEI) of ≤ 0.18 and single-head MAGNA1 ≤ 0.20, both below the maximum of 0.23 that EU ecodesign rules have set for circulators since August 2015.

Range of Versions

Single-head, twin-head and stainless-steel versions across MAGNA1 and MAGNA3.

Straightforward Commissioning

MAGNA1 is set up with one button. MAGNA3 is set up on its display or through the Grundfos GO Application Wizard.

Local Supply and Support

Tricel provides pump supply, installation, servicing and maintenance.

frequently asked questions

How do I read a Grundfos MAGNA model number?

Take MAGNA3 D 32-120 F 220 as an example. D means twin-head (no letter means single-head). 32 is the nominal port diameter in millimetres. 120 is the maximum head in decimetres, so 12 metres. F means flanged connections, and 220 is the port-to-port length in millimetres. An N in the name means a stainless-steel pump housing; without it, the housing is cast iron.

Can MAGNA pumps circulate water-glycol mixtures?

Yes. Grundfos states that MAGNA pumps can pump water-glycol mixtures with up to 50% glycol. Glycol is denser and more viscous than water, so it reduces the pump’s maximum performance. This needs to be allowed for when the pump is sized.

What liquid temperatures can a MAGNA3 handle?

The range depends on the model. For example, Grundfos specifies a liquid temperature range of -10 to +110 °C for the MAGNA3 32-120 F, with an ambient temperature range of 0 to 40 °C. Always check the data for the specific model before selection.

Can a MAGNA3 run against a closed valve?

Yes. Grundfos states that a MAGNA3 can operate at any speed against a closed valve for several days without damage to the pump.

Are there any installation restrictions?

MAGNA3 is designed for indoor installation, and the motor shaft must be horizontal. Single-head pumps for heating systems are supplied with insulating shells, which must be fitted. Shells for cooling and air-conditioning systems have different dimensions, and insulating shells are not available for twin-head pumps.

Can MAGNA3 be controlled from an external 0-10 V or 4-20 mA signal?

Yes. MAGNA3 has an analogue input that accepts a 0-10 V or 4-20 mA signal, so a controller or BMS can set the pump’s speed or setpoint without a fieldbus module.

Do the two heads on a twin-head MAGNA need to be wired together?

No. The two pump heads communicate wirelessly. On MAGNA3 D the heads are paired at the factory and connect automatically when powered on.

Can Tricel install and service MAGNA pumps?

Yes. As well as supplying MAGNA pumps, Tricel provides pump installation, servicing and maintenance. See Pump Service and Maintenance or contact our pump team to arrange installation or a service.

Need a Grundfos MAGNA Pump?

Whether you need MAGNA1 for straightforward commercial circulation, MAGNA3 for a system that needs automatic control and monitoring, or a replacement for an existing circulator, talk to Tricel about your application. We will help you identify the right pump for your system.

Call +353 (0)64 668 8040 or email watersales@tricel.ie