BoilerFaultCodesTechnical description
Return sensor above 95 °C
What causes this fault?
This fault occurs when water cannot move away from the boiler quickly enough, causing the temperature at the return pipe to spike dangerously high. The most common reasons are a seized internal pump failing to push the water or a major blockage in the pipework or heat exchanger that is strangling the flow. It can also be caused by a faulty sensor sending an incorrect high-temperature reading to the control board.
This fault often appears during the first cold spell of autumn when heating systems are turned back on after months of inactivity, which can cause internal pump components 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.