What the manual says
Manufacturer manualThe 'OVERHEAT' red indicator on the control panel will flash indicating that the overheat thermostat has operated. This will automatically switch off the boiler in the case of a control malfunction causing overheating.
From this model's manual
Verified against the Grant Vortex Eco installation & service manual.
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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