BoilerFaultCodesTechnical description
Return sensor high temperature intervention
What causes this fault?
This fault occurs when the water coming back into the boiler from your heating system is much hotter than it should be, suggesting the heat isn't being distributed to your radiators. The most common reason is that the internal pump has failed or is struggling to push water through the pipes, causing heat to build up inside the unit. In some cases, a blockage in the system or a faulty temperature sensor can also trigger this safety shutdown.
This issue often surfaces during the first cold spell of autumn when the heating is turned on after being stagnant all summer, which can cause the 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.