Emergency Lockout
16-64 on Daikin D2CND

Your boiler has shut down because the exhaust gases are getting too hot, indicating a potential blockage or safety issue in the flue pipe.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description

Flue temperature signals overheating, the flue gas discharge path needs checking, Try resetting the boiler

What causes this fault?

This fault occurs when the internal sensors detect that the exhaust gases are reaching dangerous temperatures that could damage the boiler or its surroundings. The most common reason is a buildup of debris or scale within the heat exchanger or a physical blockage in the flue pipe that prevents heat from escaping properly. In some cases, it can also be triggered by a faulty sensor sending an incorrect temperature reading to the main control board.

Engineer required

This is a emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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