BoilerFaultCodesTechnical description
Flow temperature too high. Primary sensor overheated.
What causes this fault?
This fault occurs when the boiler's internal computer brain fails to communicate properly with the other sensors and components inside the unit. It is usually caused by a physical failure of the main circuit board or a loose connection in the internal wiring harness that prevents data from traveling through the system. Because the boiler cannot verify that it is operating safely, it stops running as a protective measure.
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.
Find a Gas Safe engineer
Search the official register →