BoilerFaultCodesYour boiler's internal computer brain has developed an electrical fault and is unable to communicate with its own sensors.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: internal failure - electronic
What causes this fault?
This fault occurs when the boiler’s central control board suffers a critical internal electrical failure. It is usually caused by a component on the board burning out or a short circuit in the wiring harness that prevents the brain from sending signals to the rest of the unit.
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 406 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Ideal Systemiser SE is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.