BoilerFaultCodesYour boiler's internal computer has suffered a technical failure and is unable to control the heating or hot water operations.
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 control centre, known as the PCB, experiences a critical hardware failure or a communication breakdown between its internal components. The most common reason is an electrical short or component degradation on the circuit board itself, preventing it from safely managing the boiler's functions. In some cases, loose or damaged internal wiring can also disrupt the signals required for the system to operate.
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 407 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Ideal Response 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.