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A2

A2 — Exhaust outlet at the combustion chamber

Junkers · CERASTAR CERAMINI Boiler

What does A2 mean?

An issue with the exhaust outlet has been detected specifically at the combustion chamber. This could indicate a problem with flue gas extraction directly from the combustion area, such as a blockage.

Common Causes

  • The exhaust path at or immediately around the combustion chamber is blocked or restricted.
  • A problem with the combustion chamber itself affecting exhaust gas flow.
  • Issues with the flue system's ability to draw gases from the chamber.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the exhaust path directly at the combustion chamber for any visible obstructions or debris.

  2. 2

    Ensure the combustion chamber area is clean and free of foreign objects.

  3. 3

    If the issue persists, a qualified technician should inspect the combustion chamber and flue system for internal problems.

Browse all codes in this manual (20)
Verified technical data. Last updated: April 2026

Related Faults

A3A3 — Exhaust gas NTC on the flow control has open circuit or short circuitA4A4 — Exhaust outlet at the flow guardA6A6 — Exhaust gas NTC on the combustion chamber has an open circuit or short circuit
Source: Junkers CERASTAR CERAMINI Boiler
Open Manual (Page 34)Search more codes in this manual