Information message 523 — Low flow during defrost

What does Information message 523 mean?

The system detects insufficient water flow during a defrost cycle. The charging pump attempts to compensate by running at maximum speed. If the low flow persists, this message is displayed.

• Insufficient water flow in the system during defrost.
• Blocked filters or debris in the water circulation path.
• Problem with the charging pump or its operation.
• F2120 outdoor unit not meeting minimum firmware requirements (version 607).

Click steps to track your progress.

1. 1

   Inspect the system's water filters for any blockages and clean them if necessary.

2. 2

   Check the charging pump for proper operation; listen for unusual noises or signs of failure.

3. 3

   Verify the F2120 outdoor unit has firmware version 607 or later.

4. 4

   Update the NIBE SMO 20 firmware to the latest available version.

5. 5

   If the issue continues, contact a service technician to diagnose the flow problem.