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Viessmann Vitodens 050-W fault F4

No flame signal

Gas boiler

What it means

Burner enters a fault state because no flame signal is detected during ignition attempt.

Likely causes

  1. Faulty ignition module connection
  2. No flame signal

Where to start

  1. Confirm fan has started
  2. If ignition does not occur, fault F4 is shown
  3. Check the ignition module connection

The full answer, free

  • 5 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 57), right under the answer
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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 050-W. Check the model on the data plate before you order parts.

Other Viessmann Vitodens 050-W fault codes