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306

Code 306 - Incorrect pump type detected

Junkers · Cerapur 9000i Boiler

What does 306 mean?

The boiler's control system has detected an incorrect type of pump installed or configured. This is an R-class non-blocking interference.

Common Causes

  • Wrong pump type connected
  • Incorrect pump map setting in the system

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Set the pump map correctly in the system settings.

  2. 2

    Check the performance and wiring of the pump and relevant sensors.

  3. 3

    If the pump type is physically incorrect, replace it with the recommended type.

Browse all codes in this manual (48)
Verified technical data. Last updated: April 2026

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Source: Junkers Cerapur 9000i Boiler
Open Manual (Page 39)Search more codes in this manual