BoilerFaultCodesYour boiler has detected an electrical issue with one of its internal sensors or the gas valve, causing the system to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Sensor Fault (ST16 connector, DHW sensor, CH sensor, or gas valve electrical readings).
What causes this fault?
This fault occurs when the boiler's main control board receives an incorrect or missing electrical signal from one of its vital components. It is usually triggered by a faulty temperature sensor that can no longer measure water heat accurately, or a failing electrical connection to the gas valve which prevents the system from firing safely.
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 FAIL POINT I — no call-out fees, no surprises.
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