High
Ln on Zanussi Ultra Plus Combi

Your boiler is struggling to keep its flame lit, which means it cannot heat your water or radiators reliably.

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

Flame Loss

From this model's manual
Verified against the Zanussi Ultra Plus Combi installation & service manual.
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's internal sensor can no longer detect a steady flame after the burner has ignited. The most common reasons are a worn-out sensing probe that can't 'see' the fire, or an unstable gas supply that causes the flame to drift and extinguish prematurely.

This fault can be more frequent during extreme winter cold, as freezing temperatures can affect gas pressure or cause moisture to interfere with the ignition components.

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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