Low Information
0U on Ideal Maximiser SE

Your boiler is performing a routine safety check by blowing air through the system to clear any leftover gases before or after it fires up.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

15 seconds ventilation phase before or after operation of the unit

What causes this fault?

This code appears when the boiler's fan runs to clear the combustion chamber of any residual gases, ensuring the unit is safe to ignite. It is physically triggered by the fan spinning up to create a specific airflow, which is then confirmed by the internal pressure sensors. While usually a normal operational step, if it persists, it could indicate that the fan is struggling to reach the required speed or the air pressure switch is failing to sense the flow.

DIY fix possible

Observe the display to see if the code disappears after 15-30 secondsEnsure there are no obstructions around the external flue pipeReset the boiler if the code remains on the screen for an extended period

Find a Gas Safe engineer
Search the official register →

Related guides you might find useful

Boiler keeps losing pressure

Six most common causes of dropping pressure.

Read →

Banging / kettling / whistling noise

Each noise points to a different fault.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →