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3/c/

Blocking fault 3/c/ (2/1/7) - No air current detected after specified time

Buderus · Logamax plus Boilers

What does 3/c/ mean?

The boiler is not detecting sufficient airflow after a set period. This could be due to a blocked flue or a fan issue, and it prevents heating and domestic hot water. This is a blocking fault, requiring a manual reset.

Common Causes

  • Blocked flue
  • Faulty fan
  • Pressure switch issue

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Press the 'Reset' button on the BC10 basic controller.

  2. 2

    Check that the flue terminal is clear of obstructions.

  3. 3

    If the problem returns, contact a qualified service technician to inspect the fan and flue system.

Browse all codes in this manual (43)
Verified technical data. Last updated: April 2026

Related Faults

--/Flashing --/ - Communication fault between UBA 3 and BC10 controller0/y/Locking fault 0/y/ (2/8/5) - Return temperature sensor detected over 203°F (95°C)1/a/Blocking fault 1/a/ (3/1/6) - Flue gas sensor temperature too high
Source: Buderus Logamax plus Boilers
Open Manual (Page 47)Search more codes in this manual