BoilerFaultCodesWhat the manual says
Manufacturer manualStatus indicator during start-up/heat demand sequence
From this model's manual
Verified against the Vaillant Ecotec Exclusive Combi installation & service manual.
What causes this fault?
This status occurs when the boiler begins its internal startup process to create a flame. It is a natural part of the ignition cycle where the fan, gas valve, and electrodes coordinate to light the burner. If this code stays on screen for a long time, it suggests the boiler is struggling to establish a stable flame to begin heating.
DIY fix possible
Wait for a few minutes as this is a normal status code, not a permanent fault.Check if your thermostat is calling for heat.Ensure your gas supply is turned on at the meter.
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