BoilerFaultCodesYour boiler is notifying you that a scheduled service is due to ensure it continues running safely and efficiently.
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: E-combi oneE-System oneClas Net one CombiClas one CombiClas System one
What causes this fault?
This code is triggered by the boiler's internal timer reaching a pre-set number of operational months or ignition cycles. It is not caused by a mechanical failure, but rather a digital reminder designed to prompt a professional maintenance check. Once your Gas Safe engineer completes the service, they will reset this counter to clear the message.
This notification often appears in autumn as homeowners turn their heating back on, leading to the boiler reaching its operational hour limit after summer dormancy.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 3P9 — no call-out fees, no surprises.
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