How much does it cost to fix Ideal error code L01?

Typical repair cost for the Ideal L01 fault is £120-350 including labour.

L01 High

Ideal L01 Fault Code

Q: What does the Ideal L01 fault code mean?

Your boiler has switched itself off because internal sensors have detected it is getting too hot, which is a safety measure to prevent damage.

The Ideal L01 fault code means: your boiler has switched itself off because internal sensors have detected it is getting too hot, which is a safety measure to prevent damage.. It appears on 3 Ideal models in our database.

Technical description: Overheat Lockout

What causes the Ideal L01 fault?

This fault occurs when water inside the boiler isn't moving away fast enough, causing the temperature to rise to dangerous levels. The most common reasons are a failed pump that can't circulate the water, or a blockage within the system pipes or heat exchanger that restricts flow.

This fault is more frequent when you first turn the heating back on in autumn, as internal pump parts can seize up after months of inactivity during the summer.

Typical repair cost £120-350 (including labour)

DIY fix possible

Check that all radiator valves are fully openEnsure there are no blockages or trapped air by bleeding your radiatorsOnce the boiler has cooled down, press the 'Restart' button on the front panel

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Ideal models that show the L01 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ideal L01 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026