BoilerFaultCodesTechnical description
Safety switch-off – temperature rise too fast
What causes this fault?
This fault occurs when the heat exchanger gets too hot because the water isn't flowing away from it quickly enough. The most common reasons are a failing pump that can't push the water through or a build-up of sludge and debris blocking the internal pipework. In some cases, it can also be caused by air trapped in the system or a faulty sensor misreading the temperature.
This issue often comes to light when turning the heating back on for autumn, as pump components can seize up after being idle over the summer.
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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