BoilerFaultCodesYour boiler is currently stuck in a professional service mode used by engineers when they are replacing an internal valve.
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: Service mode / Diverter valve actuator replacement sequence step
What causes this fault?
This fault occurs when the boiler is manually placed into a specific testing mode used for replacing the motorized valve that switches between heating and hot water. It usually happens if an engineer has left the setting active by mistake or if the main control board has developed a software glitch that keeps it stuck in this maintenance sequence. Because the boiler believes it is being repaired, it will pause normal operation until the sequence is finished or cancelled.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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