BoilerFaultCodesTechnical description
Anti-cycle time
What causes this fault?
This occurs when the boiler reaches its target temperature too quickly, often because your radiators are already warm or the heating system is smaller than the boiler's output. To protect the internal components from burnout caused by constant stopping and starting, the system enforces a short rest period. It is essentially the boiler taking a 'breather' until the water temperature drops enough to start a new, efficient heating cycle.
This is more common during the spring and autumn when the weather is mild and your home requires only a small amount of heat to reach the thermostat setting.
DIY fix possible
Check that all radiator valves (TRVs) are fully open to allow heat to escape the boilerMonitor the boiler for a few minutes as it should restart automatically once the timer expiresEnsure the system pressure is between 1.0 and 1.5 bar on the front gauge