ALPHA3 15-50/60 circulator pump



The ALPHA3 has a built-in two-way communication system, which connects to the intuitive Grundfos GO REMOTE app. This enables you to easily exchange information between the pump and your smartphone.

From the moment the circulator is installed and connected,all pump operation, including setup wizard, can be controlled on your smartphone (iOS and Android). Pump settings canbe changed quickly and easily. And you get access to all relevant data, such as flow, pump performance, work log history and weekly running schedules, as well as warnings and alarms. So knowing exactly how the pump runs has never been easier.

In addition, you can balance an entire heating system through the GO BALANCE app, with real-time calculations of the flow required in your radiator and underfloor heating systems. A step-by-step guide takes you through the whole process of hydronic balancing all the home’s radiators and underfloor heating zones. Noise/heat insulation shells aresupplied as standard.

Features and benefits

  • Market-leading efficiency – low energy use compared to otherpumps in its class
  • No blockage – robust start up that reduces the need foremergency service visits
  • No dry-running – ensures that the pump protects itself fromdry run damages
  • Self-adjustable – auto-adapt automatically finds the best pumpsetting to maximise both comfort and efficiency



ALPHA3 product leaflet

ALPHA3 15-50/60 sales leaflet

Includes: technical data, pump curves and dimensions.

Pump replacement guide

Grundfos Pump Replacement Guide

The 2018/19 pump replacement guide for domestic circulators

Frequently Asked Questions - ALPHA3-system

What do I need to achieve for hydronic balancing with the ALPHA3?

  • For the ultimate benefits of the ALPHA3, installers need two other components – the ALPHA Reader and the Grundfos GO Balance app. Together, the state of the art ALPHA3 system helps installer’s complete hydronic balancing more accurately and in about half the time of traditional methods.

How is the performance of the radiator calculated?

  • The performance is calculated based on a log mean model that describes the power flow from the radiator based on the inlet temperature, the flow, and the nominal power. The inlet temperature is a user input to the App, the nominal power is the outcome of the radiator choice done in the App, and the flow is measured by the pump.

Explanation of DeltaT?

  • The delta temperature across the radiators established from the difference between the supply and return temperature. The return temperature depends on the room temperature and the flow through the radiators and is calculated by the App depended on the user input values. This means that the DeltaT presented in the App approximates what will be obtained in the branch given the conditions of the house, and can be used for evaluating the radiator design.

When the LED colour on the ALPHA READER changes from green to red, how long do I have before I need to exchange the battery?

  • This depends on battery make and temperature. When AR turns off due to power shortage simply, just exchange the battery and continue the balancing. No data will be lost.

Can I use GO balance in systems with integrated pumps?

  • In principle, it is doable – however usually boilers incorporates the pump and it will be difficult if not impossible to ensure radio transmission through the (metal) cabinet of the boiler.

Why is there a Zeroflow measurement?

  • The zero flow measurement is necessary, as the App needs to find out if there is a bypass or not in the boiler, if there is a bypass flow and to measure it’s size.

Why is there a Baseflow measurement?

  • The base flow is in principle an extra set of data needed for mathematical method to calculate the influence or resistance that is attributed to the heating unit and general piping.

What if you have two radiators, but only one combined thermostat?

  • Then they should be treated as ONE long radiator in the input fields. The reason for treating it as one big radiator is that the water through the valve affects the whole radiator, hence the flow reduction imposed by the balancing valve should be adjusted in accordance to the heat radiated from both radiators.

What should I do in the case where there is more than one radiator and thermostatic valve in a room?

  • The App supports more radiators with thermostats in the same room.

How does this compare to other hydronic balancing-calculators?

  • The great benefit of the GO-Balance is that it utilises measurements of the hydraulic parts of the heating system and thereby remove uncertainties in the calculations compared to traditional balancing tools.

Can I balance with the ALPHA3 pump in lower speed II?

  • The pump has to run at speed III to undertake the balancing. The reason for this is that the App reads the pump flow and pressure form the ALPHA3 pump and these readings have a higher accuracy when the pump runs at speed III.

Can I use GO balance in one-pipe-systems?

  • The GO-Balance is design for two-pipe systems where the heating elements are radiators. This means that it cannot be used for one-pipe system.

What is the advantage to use GO balance instead of automatic valves?

  • The automatic balancing valves will ensure that the flow in the given radiator branch is limited to the value set at the balancing valve. With automatic balancing valves, there are no need for the balancing part of GO-Balance. However, the App can be used for calculating the flow set-points for the automatic valves. The only drawback with automatic balancing valves is that they requires a fairly high differential pressure to work.

Why do I have to calibrate “Zero flow”? All valves are closed should mean no flow.

  • The zero flow calibration is necessary as the App needs to find out if there is a bypass or not in the boiler, and if there is a bypass measure the size of the bypass flow.

Which radiator power data are embedded in GO Balance for the different types and radiator sizes?

  • The data used to estimate the nominal radiator power from measureable values, such as height and length, is drawn from datasheets from radiator manufacturers.

If I lose the signal of the ALPHA Reader/MI401 on my mobile phone during balancing, can I just go back to an area with signal to continue?

  • Yes. You can put the phone down in the area where there is no signal – and then return to the valve you are about to balance. Just turn on the sound on your phone, and the sounds will help to achieve the balance. The higher the tone, the closer you are to reaching the target flow for the specific valve. When the phone makes a repeated “ding, ding, ding” sound, you have reached the flow within the target margins.

How can the principle of the calculation process of GO balance be explained (how does the app calculate the recommended flow).

  • The recommended flow is calculated based on the expected power consumption in the room, which is provided by the use by the Watt pr square meter and the number of square meter of the room. The radiator power is matched to the room power by adjusting the design flow given the expected supply temperature. Finally, the design temperature is scaled to pressure obtained by the pump in speed III. After the valves are balanced the pump should be put into AutoAdapt that will adjust the pressure to obtain the desired design flow in all radiator branches.  

Why is the calculated real flow (after balancing and after putting the pump in normal control mode like Autoadapt) not part of the report?

  • The thermostats continuously adjusts the real flow to obtain the desired room temperature. The flow adjusted during the balancing is the maximum allowed flow in the system and will only be obtained under extreme conditions. Therefore it does not make sense to show the real flow in the raport.

Is it possible to use Alpha Reader with other pumps than ALPHA3?

  • No. It is currently only the ALPHA3 that is able to “flash” data.
Sales company

Contact us

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01525 850000


Grundfos Pumps Ltd.
Grovebury Road
Leighton Buzzard
Beds. LU7 4TL

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01942 263628


Grundfos Service Ltd.
Beswick House
Greenfold Way
Leigh WN7 3XJ

How to buy

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01525 850000


Grundfos Pumps Ltd.
Grovebury Road
Leighton Buzzard
Beds. LU7 4TL