Your boiler has shut down because the water returning to the unit is too hot, which usually means heat isn't being distributed around your home properly.

Return temperature too high

What causes this fault?

This fault occurs when the water coming back into the boiler is too hot, causing the system to shut down for safety. It usually means the heat cannot escape the boiler, often due to a pump failure that isn't moving the water or a blockage in the pipework. Sometimes, a faulty sensor incorrectly reports a high temperature even when the water is cool.