High
F1 on Vaillant ecoMAX Pro 28E

Your boiler has tried to start but could not create or detect a flame, causing it to shut down for safety.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Ignition fault (lockout) Failed to light

From this model's manual
Verified against the Vaillant Ecomax Pro 28e installation & service manual, page 26.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler attempts to ignite but cannot confirm a stable flame is present. It is usually caused by a lack of gas reaching the burner, worn-out spark electrodes, or a buildup of debris on the internal components that prevents the ignition process from completing safely.

This fault can be more frequent during the first cold snap of autumn when old electrodes or gas valves struggle to operate after being idle over the summer.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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