Viessmann 200 and 222 fault fault FC

Gas valve faulty or faulty modulation valve control; or vent system blocked

Gas boiler

What it means

Burner in fault mode due to detailed code 190: gas valve faulty or faulty modulation valve control; or vent system blocked

Likely causes

  1. Faulty gas valve
  2. Faulty modulation valve control
  3. Blocked vent system

Where to start

  1. Check the gas valve
  2. Check the vent system
  3. Press reset button R

The full answer, free

  • 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