High
L01 on Ideal Logic Max System

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

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

Overheat Lockout

From this model's manual
Verified against the Ideal Logic Max System installation & service manual, page 75.
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 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.

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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