F.143 Fan overheating (air mass flow sensor / recirculation)

What the control is telling you

Burner in a fault state or locked out.

Applies to: Vitodens 200-W B2HE 85, 120, 150, 199

Likely causes

• Mass air flow sensor fault
• Flue gas recirculation

Test and repair steps

1. Reset the boiler.
2. Restart at full load with the front cover removed; if the burner restarts five times in about five minutes and locks out, replace the fan unit.
3. If the burner does not retry before lockout, inspect burner and heat exchanger for damage and replace damaged parts.
4. Reset and run at full load with the front cover fitted.

Models that show this code

4 models in Vitodens 200-W B2HE

Other codes on the same units

• F.12 Solar collector sensor short circuit
• F.13 Outside temperature sensor open circuit
• F.14 Outside temperature sensor short circuit
• F.142 CAN bus communication error
• F.15 Storage tank sensor open circuit (solar/backup)
• F.16 Storage tank sensor short circuit (solar/backup)
• F.160 CAN bus communication error (external/internal)
• F.161 BCU data memory access error