BoilerFaultCodesTechnical description
Flow temperature rise in heat exchanger too rapid
What causes this fault?
This fault occurs when the water inside the boiler heats up much faster than the system can carry it away, causing the internal safety sensors to shut the unit down. The most common reason is a blockage or a failing pump preventing the hot water from circulating through your radiators. It can also be triggered if your radiator valves are all closed or if there is excessive air trapped in the pipework.
This fault is more frequent in autumn when heating systems are switched back on after a long summer break, as internal pump components can seize during 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.