High Lockout
460 on Ideal Response SE

Your boiler's computer control board has developed an internal electrical fault and is unable to communicate properly with 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

Internal failure - electronic

What causes this fault?

This fault occurs when the boiler's internal computer brain suffers a hardware failure or a breakdown in its electrical circuitry. The most common reason is age-related wear on the circuit board's components or a sudden voltage spike that has damaged the delicate electronics, preventing the boiler from sending signals to the burner or pump.

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.

Find a Gas Safe engineer
Search the official register →

Related guides you might find useful

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →