Technical description
Active for heat/DHW request
What causes this fault?
This is not a fault; it indicates that the boiler's internal controls have successfully received a command to provide heat. It occurs when your thermostat is calling for central heating or when a hot water tap is turned on, confirming the burner is active and the system is operating as intended.
DIY fix possible
This fault may be fixable without an engineer. Check your manual first.
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