BoilerFaultCodesYour boiler is currently locked in its lowest power setting, usually because a service engineer has manually set it to this mode for testing or it is performing a self-check.
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: Forced Low mode
What causes this fault?
This code appears because the boiler has been manually instructed to run at its minimum heat output, often during a routine service or safety inspection. It is usually triggered by a technician using the internal controls to check gas pressures or flue emissions. In rare cases, a fault with the main circuit board can cause the system to get stuck in this diagnostic mode.
DIY fix possible
Check if the service mode selector switch has been left in the 'low' positionTurn the boiler power off at the fused spur for 30 seconds, then back onPress the reset button if the 'L' persists after power cycling
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A boiler cover plan would cover faults like l — no call-out fees, no surprises.
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