BoilerFaultCodesYour boiler has been manually put into a service test mode and is currently locked at a low power setting for an engineer to take measurements.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Display indicates service mode for adjustment (low load = 30% constant) when service button is pressed for 5 seconds.
What causes this fault?
This is not a mechanical failure but a specific state triggered by someone physically holding down the service button on the control panel. It happens when an engineer needs the boiler to run at a consistent low power level to accurately test the gas combustion and internal pressures. The boiler will remain at this restricted output until the mode is manually exited or the power is cycled.
DIY fix possible
Press and hold the 'Service' button again for 5 seconds to exit the modeAlternatively, turn the power to the boiler off and back on again to reset the displayIf the code persists, ensure the service button is not physically stuck or jammed
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