High Lockout
A16 on Vokera Condexa Pro

Your boiler's computer memory has developed a technical fault, preventing it from remembering the settings it needs to operate safely.

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

EEPROM ERROR The contents of the EEPROM are not correct

What causes this fault?

This fault occurs when the data stored on the boiler's internal memory chip becomes corrupted or unreadable. The most common reason is a power surge or a gradual component failure on the main circuit board, which effectively causes the boiler to 'forget' its critical safety and operating instructions.

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 fault codes

A 11View →A 17View →

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 →