BoilerFaultCodesTechnical description
High limit protection – possible flow temperature sensor not active or incorrectly located, no system circulation
What causes this fault?
This fault occurs when the water inside the boiler exceeds a safe temperature, triggering a safety shutdown. The most common reasons are a pump failure that prevents water from moving, or a buildup of debris and sludge that blocks the heat exchanger.
This issue is more frequent during the first cold spell of autumn, when pumps that have been idle all summer often seize up upon being restarted.
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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