High Lockout
PP3 on Grant Vortex

Your boiler has stopped working because an internal sensor that monitors the temperature of the heating coil is no longer sending a correct reading.

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

Coil temperature sensor failure

What causes this fault?

This fault occurs when the boiler's control board loses communication with the sensor monitoring the internal heating coil. The most common reason is that the sensor has developed an internal electrical failure or the wiring connecting it to the main board has become loose or damaged over time.

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

PP1View →PP2View →

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