Viessmann Vitodens 100-W fault 361

Flame signal not present or insufficient at burner start

Gas boiler

What it means

Burner in a fault state because the flame signal is not present or insufficient when the burner starts.

Likely causes

  1. Faulty ionisation electrode or connecting cable
  2. Loose plug-in connections
  3. Deposits on electrodes caused by foreign bodies in combustion air (laundry detergents, cleaning agents, toiletries, chimney deposits)

Where to start

  1. Check ionisation electrode and connecting cable.
  2. Check plug-in connections for loose contacts.
  3. Check the installation room and flue system for causes of deposits on electrodes, e.g. laundry detergents, cleaning agents, toiletries, deposits in ventilation air supply (chimney).

The full answer, free

  • 11 more checks in order
  • The readings and component tests from the manual
  • How to put it right, step by step
  • The manual page for this fault (page 76), 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 Vitodens 100-W. Check the model on the data plate before you order parts.

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