BoilerFaultCodesYour boiler has detected a problem with the sensor that monitors the temperature of your central heating water, meaning it can't heat your radiators safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Faulty CH thermistor or wiring
What causes this fault?
This fault occurs when the internal sensor responsible for tracking the temperature of your radiators fails to send a reliable signal to the boiler's control board. The most common reason is that the sensor has physically degraded over time or the electrical connection has become loose, preventing the boiler from knowing when to safely turn the burner on or off.
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
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