High
26 on Ideal Maximiser SE 42

Your boiler has shut down because the mixture of gas and air required for a safe flame is incorrect, often due to a blockage or a dirty internal component.

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

Improper gas/air ratio. Check the air restriction and the gas injector for the correct diameter, mounting, and pollution.

From this model's manual
Verified against the Ideal/Ideal Maximiser Se 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.

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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Boiler cover options

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All 40 fault codes on the Maximiser SE 42

Seeing a different code? Every code this model can display, in one place.

- / A- / H- / Y= / H4 / A111213141516171819202122232425272829303132333435363738394041424344E / F

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