Emergency
6.4.7 Down draft thermostat on Remeha Gas 620-510

Your boiler has sensed that exhaust fumes are blowing back into the unit instead of escaping through the chimney, which has caused 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

(optional, shut down)

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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