BoilerFaultCodesTechnical description
If the overheat Safety Temperature Limiter operates as indicated by illuminated reset light, open the controls cover and turn temperature control to “0” (anticlockwise) and then back to original position.
What causes this fault?
This fault occurs when the water inside the boiler reaches an unsafe temperature, forcing the system to shut down for safety. It is usually caused by a failure to move heat away from the boiler quickly enough, often due to a broken pump or a blockage in the internal pipework. In some cases, a faulty sensor may mistakenly signal that the unit is overheating even when temperatures are normal.
This issue is more frequent during the first cold snap of autumn when pumps that have been idle all summer often seize up upon being switched back on.
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.