What the manual says
Manufacturer manualComfort protection active. The comfort protection mode is activated.
What causes this fault?
This happens when the boiler senses that its internal temperatures are rising too quickly or are inconsistent, often due to a slight buildup of debris or a sensor that is beginning to fail. Instead of shutting down completely, the boiler reduces its heat output to protect itself from damage while still trying to keep your home warm. It is essentially the boiler's way of 'limping' along until the underlying circulation or sensing issue is fixed.
DIY fix possible
Check that all radiator valves are fully openCheck the boiler pressure is between 1.0 and 1.5 barPerform a reset of the boilerEnsure there are no external controls (thermostats) calling for heat unnecessarily
Avoid the next call-out bill
A cover plan would handle faults like S.40: no call-out fees, no surprise bills.
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