BoilerFaultCodesTechnical description
Maximum temperature - Return temperature T2 too high
What causes this fault?
This fault occurs when the water returning to the boiler is almost as hot as the water leaving it, indicating that heat is not being transferred into your radiators or cylinder. The most common reason is a failure of the external pump or a blockage in the pipework that prevents the water from circulating through your heating system. It can also be caused by all your radiator valves being closed at the same time, leaving the hot water with nowhere to go.
This fault is more common in autumn when heating systems are turned back on after a long summer break, as external pumps can seize up due to 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.