High
DHW PUMP (FLASHING) on Grant Vortex Eco External Floor Standing

Your boiler is struggling to detect the temperature of your hot water supply, which means it will likely stop heating your water until a faulty sensor or internal control board is replaced.

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

Indicates either a ‘Store’ thermistor or PCB fault.

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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