BoilerFaultCodesTechnical description
Safety cutout thermostat will extinguish the pilot and shut down the boiler in the event of overheating. Requires manual reset via button (E) after the boiler has cooled.
What causes this fault?
This fault occurs when the water inside the boiler reaches an unsafe temperature, triggering a safety switch to shut everything down. The most common reasons are a failed pump that isn't moving water away from the boiler quickly enough or a blockage in the system pipework. It can also happen if the main control thermostat fails and allows the burner to stay on for too long.
This issue often surfaces during the first cold spell of autumn when the heating is turned back on after being idle all summer, which can cause the internal pump to seize.
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.