Alarm 72 or 155 — Internal fault

What does 72, 155 mean?

An internal fault has occurred within the pump's electronics. Irregularities in the voltage supply or turbine flow can sometimes trigger alarm 72. The pump has stopped.

• Faulty pump electronics.
• Irregularities in the voltage supply.
• Turbine flow forcing an unwanted flow through the pump.
• sensor blocked by sediments if the media is impure.

Click steps to track your progress.

1. 1

   Switch off the main power supply to the pump, wait 3 minutes, then switch it back on.

2. 2

   Check for any signs of turbine flow in the application (unwanted backward flow through the pump).

3. 3

   Inspect any connected sensors for blockage by sediments, especially if impure media is used.

4. 4

   If the alarm persists, contact Grundfos Service, as pump replacement might be necessary.