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Bryan WolfeAug 1, 2025
What to do if Grundfos Water Pump light is on but pump doesn't run?
- FfgrayAug 1, 2025
If the 'Pump On' light is illuminated on the PM2 of your Grundfos Water Pump, but the pump isn't running, it could be due to a defective relay contact in the PM2 or a seized pump shaft. Check the electrical supply in the pump motor terminal box. If there's no voltage between Live and Neutral terminals, the PM2 is faulty. Also, check that the pump shaft is free to rotate.