Warning 88 — Internal sensor fault

What does Warning 88 mean?

The pump is detecting an issue with its internal sensor. It will continue to operate, but a yellow light will indicate this warning. The sensor might be blocked or faulty.

• Impurities blocking the sensor or measuring channels.
• Faulty communication from the sensor.
• sensor needs replacement.

Click steps to track your progress.

1. 1

   Check the sensor and measuring channels in the pump house to ensure they are not blocked by impurities.

2. 2

   If the warning persists, you may be able to disable the alarm in the settings menu if the sensor reading is not required for your setup (e.g., in open loop control/constant curve mode).

3. 3

   If the issue continues and the sensor reading is needed, contact Grundfos Service to replace the sensor.