BoilerFaultCodesYour boiler's computer has experienced a system failure and has entered a safety mode to prevent damage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Internal error
What causes this fault?
This fault occurs when the boiler's main control board suffers an internal electronic failure or loses proper communication with the internal wiring. It is often caused by a component failure on the circuit board itself or electrical interference that prevents the computer from executing its safety checks. Essentially, the boiler's 'brain' has detected a software or hardware glitch and has shut down to ensure it doesn't operate unsafely.
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 F0237 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Worcester Bosch Greenstar Si Combi / i System 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.