Grundfos Heating Pumps
4 fault codes documented
Pump stops, electrical error — Replace the pump
If the pump stops and the first LED is red, the system has detected an internal electrical error. This indicates a fault that typically requires professional intervention rather than user-level troubleshooting.
Pump keeps running, supply voltage low — Warning, check power supply
The pump continues to run, but a warning indicates that the supply voltage is low. This can occur if the voltage falls between 160 VAC and 190 VAC, potentially affecting pump performance.
Pump stops and is blocked — Deblock the shaft
If the pump stops and the first LED is red, the pump's shaft may be blocked. This can happen if the pump has been turned off for an extended period, allowing mineral deposits (like lime) to seize it.
First LED red — Alarm or warning status detected
The first LED on the operating panel changes from green to red, indicating that the pump has detected one or more alarms or warnings. The pump may stop or continue running depending on the specific alarm.