High Lockout
E13 on Baxi Avanta

Your boiler has sensed a dangerous level of overheating within its internal system and has locked itself down as a safety precaution.

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

Heat exchanger thermal fuse tripped

What causes this fault?

This fault occurs when the boiler's internal temperature reaches a critically high level, causing a safety fuse to blow and permanently cut the power to prevent a fire or explosion. It is usually caused by a severe lack of water circulation, a major blockage in the heat exchanger, or a complete failure of the internal pump. Unlike a standard overheat, this fuse is a one-time safety component that cannot be reset electronically.

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

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