BoilerFaultCodesTechnical description
Permanent fault. Critical flow temperature reached, non-existent or insufficient circulation.
What causes this fault?
This fault occurs when the water inside your boiler gets too hot too quickly because it isn't moving through the pipes as it should. The most common reasons are a failed internal pump that can no longer push the water, or a blockage such as a build-up of sludge or debris within the system.
This issue is frequently seen when heating is first turned on in autumn, as internal pump parts can seize up after being inactive during the summer months.
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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