BoilerFaultCodesTechnical description
Flue gas probe error for having exceeded the temperature limit (with this error, the fan operates at max.)
What causes this fault?
This fault occurs when the internal sensors detect that the exhaust gases have reached a dangerously high temperature, which is often a sign that heat isn't being transferred effectively to the water. The most common reasons are a heavy buildup of limescale or debris inside the heat exchanger, or a physical blockage within the flue pipes preventing proper ventilation.
This issue often comes to light during the first cold spell of autumn or winter when the boiler is required to run at maximum output for long periods.
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.