In this module, you will learn how to interpret the ALPHA GO range’s warnings and alarms, so you can diagnose problems and better manage troubleshooting issues.
The ALPHA1 GO and ALPHA2 GO pumps are equipped with clear indicators to help identify and resolve potential issues. Let’s explore the warnings and alarms, what they mean, and how they’re displayed.

The yellow LED signals a warning, meaning the pump is operating but not performing optimally. Immediate action is usually not required unless it causes under-heating or discomfort. Events that trigger the yellow LED include:

Under-voltage while running. The pump detects low voltage but continues to operate, indicated by the yellow LED and the error code E2. This warning will show on both ALPHA1 GO and ALPHA2 GO. The ALPHA2 GO event log will register this warning.

When an external signal is detected but hasn't been activated in the Grundfos GO app, the pump will indicate a warning by the yellow LED and an E9 error code. To resolve this, use Guided Setup to activate the external signal control.

Forced pumping. Other pumps or sources may generate flow through the pump, even when it is switched off. This is indicated by a yellow LED and error code E3. To resolve this, check the system to ensure the non-return valves are correctly positioned and inspect for any defective valves. Replace the valves if necessary.

The spinner icon indicates temporary states where no action is needed. For example: Commissioning or detecting water. During initial setup, the spinner shows the pump is being commissioned. It also runs if the pump is attempting to detect water. The system should resume normal operation automatically.  

Air detection and venting during operation. Enabled via the Grundfos GO app, the ALPHA2 GO will automatically detect and vent air. When this occurs, the spinner will appear.

Software updates. The spinner also appears during ALPHA2 GO software updates, temporarily pausing normal operation until the process is complete. The ALPHA2 GO event log will register this event.

The red LED signals an alarm, meaning the pump has stopped and requires immediate attention. Alarms include: Dry run qualification and stop. If the pump detects a potential dry running scenario, a spinner icon will appear. If dry running occurs, the pump will automatically stop, indicated by the red LED and error code E4. This alarm will show on both ALPHA1 GO and ALPHA2 GO. The ALPHA2 GO event log will register this alarm. To resolve a dry running issue, fill the system with the correct amount of liquid, then prime and vent the pump before starting it up again.

Pump blocked. In the unlikely situation that the pump becomes physically blocked, the red LED will light up along with the error code E1. This alarm will show on both ALPHA1 GO and ALPHA2 GO. The ALPHA2 GO event log will register this alarm. Only a qualified specialist should attempt to unblock the pump. First, isolate the pump, then remove the pump head, and finally remove the deposits.

Electrical fault. If an electrical issue stops the pump, this will be indicated by the red LED, along with error code E3. This alarm will show on both ALPHA1 GO and ALPHA2 GO. The ALPHA2 GO event log will register this alarm.  If the pumps stops while the LED displays red with error code E3, this could indicate one of the following:

Overvoltage. The supply voltage to the pump is too high. To fix this, ensure the power supply is within the specified range.

Internal faults. The pump must be replaced. Contact Grundfos Service or dispose of the pump in an environmentally responsible manner according to local regulations.

E3 can also indicate that the ALPHA2 GO is missing software if a factory reset of the pump is initiated. Re-connecting to the ALPHA2 GO with the Grundfos GO App should automatically solve this issue. If there is noise in the system, it could be due to one of the following reasons. The flow is too high. To fix this, lower the flow.

There is air in the system. To resolve this for the ALPHA2 GO, connect to Grundfos GO, select the settings menu, choose system and pump venting, change the duration to 10 minutes and press start venting. This event will be recorded in the ALPHA2 GO event log. For ALPHA2 GO, additional insights are available through the Grundfos GO app, including detailed event logs that record warnings and alarms for easier troubleshooting.

Let’s recap.
Yellow LED. Indicates a warning—monitor the system and act only if performance is affected.

Red LED. Signals an alarm—requires immediate attention to resolve the issue.

Spinner icon. A temporary state for commissioning, water detection, air purging, or software updates—no action is needed, the pump will return to normal automatically.