High Lockout
3 6. on Remeha Quinta Ace 25

Your boiler has detected that a key internal thermometer is broken or disconnected, meaning it cannot safely monitor the temperature of the water leaving the unit.

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

Temp.sensor fault: Flow temperature sensor defective or not connected.

What causes this fault?

This fault occurs when the boiler's control board loses communication with the sensor that measures the heat of the water being sent to your radiators. The most common reason is that the internal sensor has physically failed due to age or heat stress, though it can also be caused by loose wiring or dampness affecting the electrical connections.

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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