Viessmann 200 and 222 fault fault EF

Flame is lost immediately after it has built (during the safety time)

Gas boiler

What it means

Burner in fault mode due to detailed code 138: flame lost immediately after building, during the safety time

Likely causes

  1. Gas supply issue
  2. Flue gas recirculation
  3. Ionization electrode distance or contamination issue

Where to start

  1. Check gas supply (gas pressure and gas regulator)
  2. Check flue gas/ventilation air system for flue gas recirculation
  3. Check ionization electrode (replace if required): distance to burner gauze assembly

The full answer, free

  • 2 more checks in order
  • How to put it right, step by step
  • The manual page for this fault (page 2), right under the answer

Safety: Isolate gas and power before you open the case. If you have been into the gas side, do a tightness test, and a combustion and flue check before you hand back. Gas Safe (UK) or RGI (Ireland) work only.

From the Viessmann manual for the 200 and 222 fault. Check the model on the data plate before you order parts.

Other Viessmann 200 and 222 fault fault codes