BoilerFaultCodesTechnical description
Temperature is too high during central heating demand.
What causes this fault?
This fault occurs when the water inside the heat exchanger reaches a dangerously high temperature because it cannot move through the system effectively. The most common reasons are a failed circulation pump that is no longer pushing water around or a blockage caused by a build-up of sludge and debris in the pipework.
This issue is more frequent during the first cold snap of autumn when pumps that have been idle all summer often seize up or struggle to move heavy sludge.
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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