BoilerFaultCodesTechnical description
Overheat - Normally associated with either poor or lack of primary water circulation. Wait for appliance to cool then reset as described for code 01.
What causes this fault?
This fault occurs when the water inside the boiler exceeds a safe temperature, triggering a safety sensor to shut the system down. The most common reason is that the water is unable to move through the pipes quickly enough to carry heat away, often due to a broken pump or a blockage in the system. It can also be caused by a build-up of limescale or debris within the heat exchanger that prevents efficient heat transfer.
This fault is more frequent during the first cold spell of autumn, when pumps that have been idle all summer often seize up upon being switched back on.
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.