1Problems when replacing a circulation pump (and how to avoid them)

For any heating installer, replacing a circulation pump should be a simple task. In practice, however, it rarely is. The most frequent obstacles in the process of how to replace a circulation pump are well known:

• Insufficient stock: It's impossible to carry all pump models available on the market in the van. The usual result is a second trip to the supplier or waiting for delivery of the specific part.
• Selection complexity: Identifying the correct model to replace an integrated UPS, UPM3 or UPM4 pump requires knowing the performance curve, dimensions and compatibility with system signals. Finding Grundfos pump equivalents consumes valuable time on site.
• Inaccurate commissioning: Installing the pump without the correct configuration can generate noise, excessive consumption or loss of comfort in the heating system, resulting in a callback from the customer.
• No documentation: Upon completing the installation, the installer can rarely provide a technical report to the owner, which generates distrust and complicates future maintenance.

Grundfos has developed the ALPHA GO range precisely to eliminate these bottlenecks, leveraging decades of experience in integrated circulators. Below we'll see how two models solve almost the entire problem.

2What is Grundfos ALPHA GO and how it works

The ALPHA GO range is the latest generation of Grundfos' successful ALPHA family, which has been a world reference in circulation pumps for domestic heating for decades. The "GO" suffix is no coincidence: it refers directly to the Grundfos GO application, which becomes the central tool of the entire ecosystem.

The fundamental principle of the ALPHA GO range is radical in its simplicity: with only two models in the van —the ALPHA1 GO 25-80 180 and the ALPHA2 GO 25-75 180— plus an FCI signal adapter, an installer can solve almost 70% of all circulation pump replacement scenarios, both integrated and standalone.

The compatibility distribution between the two models, or Grundfos pump equivalence, is designed to cover the complete spectrum of the installed base:

3ALPHA1 GO: which pumps it replaces and how to install it

The Grundfos ALPHA1 GO is the standard range solution within the ALPHA GO family, designed for quick and reliable replacement of integrated UPS pumps and conventional standalone circulators. It incorporates a high-efficiency electronically commutated motor (ECM).

ALPHA1 GO 25-80 180 — Key points

• High-efficiency ECM motor
• The 25-80 180 model has 8 m head
• Covers 70% of integrated UPS pumps on the market
• Automatic air venting on startup
• Dry-run protection
• Robust startup against blockages (dirt, lime, magnetite)
• 3 control modes: Constant P., Proportional P., constant curve
• Assisted configuration via GO app (manual adjustment on panel)

• Integrated and standalone compatibility: Replaces both pumps integrated in boilers and standalone circulation pumps, eliminating the need for two different references.
• Automatic air venting: The system automatically removes air from the pump on startup, without the installer having to perform this process manually. Saves time and prevents operational problems.
• Dry-run protection: The pump detects the absence of water and stops preventively, protecting the component and significantly extending its service life.
• Robust startup: If the rotor is blocked by accumulation of dirt, magnetite or lime, the motor continuously retries startup at maximum possible torque, guaranteeing operation even in difficult conditions without external intervention.
• Three control modes: Constant pressure, proportional pressure and constant curve, each with three speed settings configurable from the control panel.
• Fault location: Error codes visible on the pump's own control panel for quick diagnosis.

Although the ALPHA1 GO does not have direct Bluetooth connectivity with the application (unlike the ALPHA2 GO), the installer can benefit from the GO Replace functionality to obtain the precise settings that must be manually entered on the pump's control panel:

4ALPHA2 GO: the best option for UPM3, UPM4 and modern systems

The Grundfos ALPHA2 GO is Grundfos' bet on maximum digitalization in compact circulation pumps. Designed to replace integrated UPM3 and UPM4 pumps, as well as high-efficiency standalone circulators. Its great differentiator is the integrated Bluetooth connectivity, which allows communication with the Grundfos GO app in real time.

If you're looking for which pump replaces the UPM3 or what is the equivalent to the Grundfos UPM4, the answer is the ALPHA2 GO 25-75 180 with the FCI adapter.

ALPHA2 GO 25-75 180 — Key points

• Built-in Bluetooth — direct connectivity with GO app
• Enhanced AUTOADAPT (Constant P. and Proportional P.)
• Step-by-step Guided Setup via app
• Automatic and shareable installation report
• Hydraulic balancing via app
• Automatic night mode
• Historical log: flow, pressure, temperature and cycles
• OTA firmware update via app
• 4 control modes + AUTOADAPT
• Up to 55% certified energy savings

The ALPHA2 GO communicating in real time with the Grundfos GO app via Bluetooth — without any additional device.

In addition to all the features of the ALPHA1 GO (automatic air venting, dry-run protection, robust startup), the ALPHA2 GO incorporates:

• Guided Setup via app: The most important feature of the ALPHA2 GO. The app provides step-by-step instructions considering all critical system factors (number of zones, system type, desired return temperature) to achieve the most accurate commissioning possible. Upon completion, it automatically generates a shareable report.
• Enhanced AUTOADAPT: The algorithm has been optimized to also work in constant pressure mode (not just proportional as in previous generations). It automatically adapts to high short-term heat demands and system load changes.
• Air detection and active venting: The pump detects air around the impeller and activates a pulsing operation mode to effectively push this air towards the system's venting points.
• Hydraulic balancing: Through the app, it allows adjusting the system to achieve uniform heat distribution, reducing energy consumption and ensuring correct supply temperatures in each zone.
• Real-time alerts and alarms: Proactive notifications about possible operational problems, accessible directly from the app via Bluetooth.
• Night mode: The pump automatically detects the boiler's night operation mode (reduced supply temperature) and adjusts its operation to maximize energy savings.
• Trend and event logging: Historical data of flow, head, estimated fluid temperature and cycle durations, accessible from the app for analysis and troubleshooting.
• Four control modes: Constant pressure, proportional pressure, constant flow and constant curve, all accessible and configurable from the app.
• OTA firmware updates: Through the app, it's possible to update the pump's firmware to always maintain the latest features and improvements.

In the case of replacing integrated UPM3 or UPM4 pumps, the ALPHA2 GO connects directly with the app to automatically replicate the performance of the replaced pump. This direct connection via Bluetooth guarantees precise configuration that saves time and ensures optimal system performance without additional manual steps.

5ALPHA1 GO vs ALPHA2 GO comparison: complete table of differences

If you're evaluating ALPHA2 GO reviews or simply need to know which model to choose for each situation, this table collects all the key technical differences:

6Grundfos GO App: GO Replace and step-by-step Guided Setup

The Grundfos GO application is the digital heart of the entire ALPHA GO experience. Available for free for Android (Google Play) and iOS (App Store), it acts as the installer's personal assistant in every phase of the work.

Grundfos GO app interface: GO Replace, Guided Setup and real-time monitoring. Free download on Google Play and App Store.

GO Replace for circulators is the functionality that solves the installer's most common problem: how to replace a Grundfos circulation pump without errors. It offers two methods of use:

• Scan-find-replace: The installer points the phone's camera at the data matrix code or nameplate of the existing pump. The app automatically identifies it and provides a precise replacement suggestion with the correct ALPHA GO model.
• Search and select: If the code is not readable, the installer manually enters the model name or product reference. The app returns the replacement suggestion with the necessary configuration settings.

Guided Setup is, according to Grundfos, the most important feature of the ALPHA GO ecosystem. Through direct Bluetooth connection with the ALPHA2 GO, the app takes the installer through a process of structured questions about the system (installation type, number of zones, pipe system, desired return temperature) and automatically calculates the optimal control mode and setpoint for that specific system.

The result is a pump configured with the highest possible accuracy, without depending on the individual installer's criteria or reference tables. Upon completion, the app generates a complete installation report that can be shared by email with the owner.

For the ALPHA2 GO, the Grundfos GO app also functions as a real-time diagnostic tool. The installer can consult:

• Historical data of flow, head and estimated fluid temperature
• Event and alarm log with timestamps
• Operating cycle durations to detect anomalous patterns
• Firmware status and update availability

7How to install a Grundfos ALPHA GO circulation pump step by step

The circulation pump installation step by step process for ALPHA GO pumps has been designed to minimize time at each phase. The official Grundfos Ecademy training modules detail the complete procedure:

Complete installation process of the Grundfos ALPHA2 GO. Images: Grundfos.

Both the ALPHA1 GO and ALPHA2 GO incorporate a tool-free installation connector that simplifies the wiring process and can be rotated 90° to adapt to the installation. In the case of replacements, the available power adapters (ALPHA, Volex, Molex) allow connecting the old cable without cutting or rewiring it.

• FCI adapter: Necessary when replacing UPM3 or UPM4 pumps managed by external signal. Connects the signal cable to the Superseal port of the ALPHA2 GO.
• ALPHA power adapter: Recommended for replacing previous ALPHA1, ALPHA2 and ALPHA3 generations. Connects the old cable without cutting.
• Volex and Molex adapters: For replacing UPS pumps with specific connectors without the need for rewiring.

8Energy savings and efficiency: up to 55% less consumption

One of the strongest commercial arguments of the ALPHA GO range is the direct impact on the owner's energy bill. When replacing an old pump with a correctly configured ALPHA GO, the savings can be very significant.

Grundfos certifies that the ALPHA2 GO, thanks to its high-efficiency ECM motor and enhanced AUTOADAPT algorithm, can achieve installations with up to 55% energy savings compared to old low-efficiency circulation pumps, without compromising heating comfort.

The AUTOADAPT algorithm is the engine of efficiency in the ALPHA2 GO. It continuously adapts the pump speed to the actual heating demand of the system at each moment, avoiding unnecessary consumption when demand is low. The improvements of the new generation are:

• Now also available in constant pressure mode (not just proportional)
• Optimized for short-term peak heat demands
• Improved management for systems with frequent load changes

Hydraulic balancing available through the Grundfos GO app for the ALPHA2 GO ensures that all radiators and zones of the system receive the correct flow. A hydraulically unbalanced system forces the pump to work at higher pressure and consume more energy than necessary. With correct balancing you achieve:

• Correct return temperature, improving the performance of condensing boilers, as in any well-balanced system
• Elimination of cold zones and overheating
• Reduction of the overall energy consumption of the heating system

9Free Grundfos Ecademy training — Course 103: ALPHA GO Range

Grundfos makes available to all installers a free 7-module online training course on its Grundfos Ecademy platform, specifically designed for the ALPHA GO range. The modules cover the entire workflow with the new pumps in just 40 minutes.

Course 103 — ALPHA GO Range on Grundfos Ecademy. 7 modules, 40 minutes, intermediate level, 5/5 star rating. Completely free for registered installers.

10Frequently asked questions about Grundfos ALPHA GO