BoilerFaultCodesYour boiler is operating at its maximum heating capacity and has entered a temporary monitoring state, which is usually part of normal operation or a simple setting adjustment.
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: Max. heating output
What causes this fault?
This code appears when the boiler has reached its highest possible heat production and is working at full power to meet the demand you have set. It is often triggered if the thermostat is set very high or if the heating system is trying to warm up a very cold house quickly. It is considered a status message rather than a mechanical failure, indicating that the system is simply running at its limit.
This display code is most common during the first cold snap of winter when the heating is turned on after a long break and the boiler has to work harder to reach the target temperature.
DIY fix possible
Check that your radiator valves are fully openEnsure the system pressure is between 1 and 1.5 bar on the front gaugeTurn the heating control knob down slightly and restart the boiler
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A boiler cover plan would cover faults like 5.0 — no call-out fees, no surprises.
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