BoilerFaultCodesTechnical description
Return probe error for having exceeded the temperature limit
What causes this fault?
This fault occurs when the sensor detects that the water coming back into the boiler from your radiators is much hotter than it should be. The most common reasons are a blockage in the system or a failing pump that isn't moving the water fast enough, causing it to overheat within the heat exchanger. In some cases, the sensor itself may have developed a fault and is giving an incorrect temperature reading.
This issue is more common during the first cold spell of autumn, when the heating is turned back on after months of inactivity and the internal pump has seized or stuck.
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.