High Lockout
A61 on Ferroli Modena HE

Your boiler's main internal computer has developed a technical fault and can no longer communicate with the rest of the system.

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.

Technical description

Controller ABM03B error – controller has an internal error

What causes this fault?

This fault occurs when the boiler's central control board suffers a hardware failure, meaning it can no longer send or receive instructions to vital components like the pump or gas valve. The most common reason is that the delicate electrical circuits on the main PCB have burnt out or degraded, often due to age or an unexpected electrical surge.

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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Related fault codes

A01View →

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