BoilerFaultCodesYour boiler has detected a fault with a internal sensor that monitors the temperature of the water used to heat your radiators, 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: CH flow thermistor short circuit or damaged
What causes this fault?
This fault occurs when the boiler's internal computer receives an impossible electrical signal from the sensor that monitors the temperature of the water heading to your radiators. The most common reason is that the sensor has suffered an internal electrical failure or the wiring connecting it to the main control board has become damaged or loose.
This fault is frequently seen when heating systems are first turned back on in autumn, as the sudden increase in thermal stress can cause a weakened sensor to finally fail.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like E2 — no call-out fees, no surprises.
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