Emergency
E047 on Navien NCB 28 HE

Your boiler has detected that the temperature in the exhaust flue is too high, causing it to shut down for safety reasons.

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

Abnormal operation: exhaust thermostat

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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