BoilerFaultCodesTechnical description
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.
This fault is frequently seen at the start of autumn when heating systems are turned on for the first time after summer, as pump components can seize up during long periods of inactivity.
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.
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