BoilerFaultCodesYour boiler's temperature sensor has failed or has a wiring issue, which means the system cannot safely monitor how hot the water is or provide heating and hot water.
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 open circuit
What causes this fault?
This fault occurs when the internal sensor responsible for monitoring the temperature of the water leaving the boiler fails to send a clear signal to the main control board. The most common reason is that the sensor's internal electrical resistance has broken down over time, or the wiring connecting it has become loose or damaged. Because the boiler no longer knows how hot the water is, it shuts down as a safety precaution to prevent overheating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like E2 — no call-out fees, no surprises.
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