BoilerFaultCodesTechnical description
Safety switch off temperature difference too great
What causes this fault?
This fault occurs when the internal water temperature rises too quickly because the heated water cannot leave the boiler fast enough to reach your radiators. The most common reason is a pump failure or a significant blockage in the system, such as a build-up of sludge or debris, which prevents the water from circulating properly.
This fault is most common when you first turn the heating on in autumn, as internal pump parts often seize up after being inactive throughout the summer months.
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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