ALPHA3 circulator pump - heating, cooling



The Grundfos ALPHA3 marks the start of a new era in domestic circulators for installers. With the ALPHA3, it’s never been quicker or easier to operate a pump within domestic heating systems.

Through the Grundfos GO Remote app, the ALPHA3 is now controlled directly on your smartphone, making pump setup and monitoring simpler than ever. The ALPHA3 also comes with built-in functionality to perform easy flow-based hydronic balancing with the Grundfos GO Balance app.

Full control via your smart device

The ALPHA3 is fully controlled via your smart device. It utilises integrated Bluetooth communication that connects to the intuitive Grundfos GO Remote app, ensuring smarter and more optimal operation. This enables you to easily exchange information between the pump and your smart device. From the moment the circulator is installed and connected, all pump operation, including setup wizard, is available in the GO Remote app (iOS and Android).

Grundfos GO Remote

Grundfos GO Remote is our easy-to-use platform for remote product control, selection and information. It offers you fast and intuitive control of all pump features for connected pumps such as the ALPHA3. It also gives you direct access to our online tools, saving valuable time on reporting and data collection.


Grundfos GO Balance guides you through every step of flow-based hydronic balancing with the ALPHA3 to make the process quick and easy. GO Balance is the first-ever mobile platform for hydronic balancing of two-pipe radiator and underfloor heating systems, providing documentation and saving you time.

The Grundfos ALPHA3 is suitable for:

  • One and two-pipe radiator systems
  • Underfloor heating systems
  • Suitable for air-conditioning systems with liquid temperatures ≥ 2 °C

Key features and benefits:

  • Built-in hydronic balancing
  • Full control via Grundfos GO Remote app, offering step-by-step assistance for pump configuration, maintenance and commissioning
  • Dry-running protection during start-up and operation
  • Robust restart enables the pump to continuously attempt restarting with the highest possible torque
  • AUTOADAPT automatically adjusts to the best pump setting in radiator and underfloor mode
  • Market-leading efficiency
  • Low noise level


  • Fully controlled via smart device
  • Assisted pump setup and hassle-free and operation
  • Easy hydronic balancing of heating systems and corresponding pump setup





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.

Grundfosliterature-6119685.pdf (467 KB)







Spare parts



Frequently Asked Questions - ALPHA3-system

Are there subsidies for end users available for exchange of old pumps and hydraulic balancing

  • Local legislation governs this. In Germany there is existing opportunity to receive subsidies for new build and renovations- Plans are pending for a major circulator replacement scheme in Germany though not voted upon in parliament yet.

Will the GO balance heat load estimation be accepted after 2016 (VdZ Verfahren A: specific heat load / Verfahren B: DIN EN 12831)? Is it planned to extend the app by DIN EN 12831 calculation?

  • It is not in our current plans to extend GO Balance to cover DIN EN 12831. We will however continue to monitor the direction of German legislation during 2016.

Is hydraulic balancing with GO balance an officially accepted procedure (e.g. KfW)

  • In Germany yes – this is in accordance with KfW and GO Balance even documents beyond the requirements in KfW.

When the LED color on ALPHA READER change from green to red, how long can I proceed balancing before I need to exchange battery?

  • This depend 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 (exchange the pump in the boiler against A3)

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

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 DeltaT?

  • The delta temperature across the radiators is found 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.

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 and, if there is a bypass flow, measure the size of the bypass flow.

Why is there a Baseflow measurement?

  • The internal hydraulic resistance of the heating source (boiler, heat pump, etc.) is often considerable in size and is therefore necessary for calculating the pump pressure. The algorithm in that app that calculates the internal hydraulic resistance uses the measured base flow and therefore needs this base flow measurement, which is found by opening the two valves with the highest flow.

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

  • Then they should be treated as ONE long radiator in the input fields. The reason for treating it as one big radiators is that the water through the valve affect 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 to do in the case where there are more than one radiator and thermostatic valve in a room? (The designation thermostatic valve should be replaced by heating coil, radiator or similar)

  • The App supports more radiators with thermostats in the same room. In this case, the App divides the needed heat power for the room between the radiators in accordance with the radiator sizes. Such that the lager radiators are expected to deliver a larger amount of the heat power compared to the smaller radiators.

Accuracy of target flow determination – how much does it count to do it?

  • It is not possible to adjust to the exact target with many types of balancing valve system. Fortunately, it is not important to adjust to the exact valve just that the flow is inside the green area then the heating system will operate as intended.

Comparishment to other hydronic balancing-calculators

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

Can I do a balancing with the ALPAH3 pump in lower speed II?

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

Can I use GO balance in one-pipe-systems

  • The GO-Balance is design for two-pipe system 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 (Heimeier Eclipse etc.)

  • 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 difference pressure to work.

Can I use GO Balance when automatic valves (example Heimeier Eclipse) are installed

  • With the automatic balancing valves, the maximum allowed flow in the radiator branches of the heating system is adjusted directly. The GO-Balance App can be used for calculating the flow set-points for the automatic valves, whereas the balancing part of the App is not design for this type of valves and can therefore not be used in this type of system.

Can I use GO balance in Tichelmann Systems

  • The Tichelmann system is just a special type of two-pipe system. The GO-Balance works with two-pipe system heated with radiators, meaning that it can very well be used in a Tichelmann system.

Can I use GO balance in systems without pre-adjustable valves AND without return valves

  • It is of cause not possible to balance a system without balancing valves. However, with GO-Balance it is possible to calculated, on which radiator branch a balancing valve should be installed to obtain a well-balanced system.

Can I use Go balance in systems with relay valve (Überströmventil). Do I have to consider anything there?

  • Automatic bypass valves typically opens with increased pressure. The App is not designed for operating with active automatic bypass valves. Therefore, it is recommended that the automatic balancing valve is closed or adjusted to the highest possible opening pressure during the balancing routine. Note that when closing the automatic bypass valve the boiler is in risk for overheating, therefore it is very important that the boiler is switch off during the balance routine in this case.

Why do I NOT have to type in return temperature in GO Ballance to define Delta T

  • The return temperature depends on the supply temperature, the room temperature, and the flow through the radiator. All these values are known in the App, and are used for calculating the actual return temperature that will be obtained for the radiator. The App uses the calculated return temperature and the supply temperature to calculate Delta T. The use of the calculated return temperature ensures the resulting Delta T is the one actually obtainable with the given system configuration.

When I use radiator type 4/”unknown radiatortype” (Sonstige) and type in the radiator power: do I have to type in the Normheizkörperleistung (75/65/20) or the radiator power related to the real (selected) flow temperature

  • You use the nominal radiator power when operating under 50/20 conditions, i.e. with a mean radiator temperature 50°C above room temperature. Commonly listed in datasheets as “75/65/20” or “80/60/20” ratings. Has to be written as SI-value [W].

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 attracted from datasheets from radiator manufacturers such as Riopanels, Stelrad, hg-tec, Yongkang Huand etc.. Data is only attracted for radiators whish fulfills the standards within EN 442-1.

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

  • Yes. You can put the phone down in the area where there is 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 lead you to balance. The higher the tone, the closer you are at 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 of being balanced.

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.

 If you choose concrete and wood floor you cannot choose a higher room temperature than 19 degrees?

  • You can, the floor type does not influence your options for desired room temperature + Different materials has different max allowed temp which should be obeyed.

What is the base flow used for?

  • Base flow define all the resistance in the UFH system  and have this data available for the APP to do the right calc. The base flow is used for the estimation of the flow resistance in the manifold and shunt.

Can GO Balance be use for fan coils and underfloor systems?

  • We only support radiators and underfloor heating system- Two string Radiator systems with preset valves/ Lock shield valve.

Is the Alpha Reader V2 compatible for UFH?

  • Yes, it is the same system for radiators and UFH.

How would you know the load distribution between radiators and UFH?

  • We calculate how much power the radiators and the UFH can deliver and ask the user to distribute the remaining ( available heat energy ) power between the two systems.

How long did the balancing take in field test for underfloor or even mixed systems?

  • from ½ hour up to 3 hours as it was a learning experience
  • We have made some field tests - and as users get experience, it becomes faster. It is fairly fast.

Will we have video demo for UFH balancing process?

  • Yes - we have prepared video for UFH and radiator, and we will have one for combined as well. (You can find videos at YouTube you tube under Grundfos go Balance, ALPHA3.

When will it be possible to see precise flow at the screen? Not only flow mark? On line

  • There is no plan of implementing this.

Some heating systems include both UHF and radiators working with one pump (manifold has not own pump). Is it possible to balance these systems with GO Balance app?

  • No, we do not support radiators and underfloor heating connected to the same pump.

Could you please explain (in details) how it is possible to measure such a small flow in a system, when pump work in a zone extremely close to the zero flow (closed valve). In this duty point eta is very low, and consumed power also very low.

  • We perform the measurements and the balancing with the pump at maximum speed to ensure as large flows in the system as possible. During the process we measure the flow in the system with all valves closed and during the balancing we compensate for this zero flow when determining the flow value in the valve. Furthermore we have a minimum flow during the balancing to ensure that the flow in the valve is large enough to measure.  

Does the app for radiators consider the question if the valve design is for 1K or 2K p-band?

  • No it does not. The radiators are balanced so the radiators power output at maximum flow matches the radiators share of the power loss in the room it is in.

What is really measured? During measurement the pump delivers almost 6 meter head in speed III, and after balancing you switch to AUTOADAPT - low head - what happens with real flow in a system?

  • The flow and head will become lower when the pump is set in AUTOADAPT. The flow we achieve during the balancing is not the design flow, it is up-scaled from the design pressure to the maximum pressure.

If an installer has a pretty good project with a precise flow for each radiators – a display of the real flow is a feature we need - could you please display the real flow and head in a system in a Go Balance app?

  • It is an estimation not a measurement - we have a good enough relative flow measurement . The absolute measurements is not precise enough to be used for the balancing purpose.

How is balancing performed in your country today?

  • In Sweden, I guess that in best cases look up tables are used for balancing thermostats. In most cases "gut feeling" or nothing at all...(When we talk about households).

Does the app for radiators consider the question if the valve design is for 1K or 2K p-band?

  • No it does not. The radiators are balanced so the radiators power output at maximum flow matches the radiators share of the power loss in the room it is in.

What is the prerequisite for UFH?

  • A UFH system with preset valves. To balance a UFH system we must be able to estimate flows in the floor pipe loops. We cannot do balancing if the system has a permanent by-pass.

Is thermostats in the room mandatory in order to balance an underfloor heating system?

  • Yes, since we balance to achieve a required room temperature the system must provide means for a user to set the room temperature as well as feeding actual room temperature back to the controller.

Is there a difference between hydraulic & hydronic balance?

  • There is no difference between the two. Hydraulics is the field of fluid mechanics and hydronics is the field of liquid based heating and cooling systems. We are using our hydraulic knowledge to balance a hydronic system, so you can use both terms in this context.

What do I do if an underfloor heating zone valve opens unexpectedly?

  • Some underfloor heating systems has an automated valve exercise function, that can open the zone valves unexpectedly during the balancing procedure. If this happens you must remove the opened valve actuator, and manually close the valve.
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