High
E04 on Keston Qudos 28S

Your boiler is struggling to keep its flame lit while in operation, which means it has safely shut itself down to prevent any issues.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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 failure whilst running - the boiler is having difficulty maintaining the flame. Consult your Service Engineer and check for flue, gas supply or condensate drainage obstruction

From this model's manual
Verified against the Keston Qudos 28s installation & service manual, page 38.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

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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