BoilerFaultCodesTechnical description
Operates if the water flow rate through the boiler is inadequate; requires manual reset by pushing in the 'reset' button.
What causes this fault?
This fault occurs when the water inside the boiler exceeds a safe operating temperature, triggering a safety shut-off to prevent damage. It is usually caused by a blockage in the system or a failing pump that is no longer moving hot water away from the heat exchanger quickly enough. In some cases, the internal sensor responsible for monitoring heat may have developed a fault and is providing an incorrect reading.
This issue often surfaces when the heating is first turned on after summer, as pump components can seize during long periods of inactivity.
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.