High
Boiler Fault Finding 9 on Grant Vortex Pro 15-26

Your boiler has detected that it is becoming dangerously hot and has shut itself down to prevent damage, likely because water is not flowing through the system properly.

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

Boiler operating on overheat thermostat. Faulty boiler thermostat. No circulation, check circulating pump. Check for air lock.

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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