BoilerFaultCodesYour boiler has detected a problem with a temperature sensor, meaning it cannot accurately monitor the heat levels needed to warm your home.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
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What causes this fault?
This fault occurs when the boiler loses communication with the sensor responsible for monitoring the temperature in your living area. It is typically caused by a faulty component failing to send a signal or a break in the electrical wiring connecting the sensor to the boiler's main control board.
This issue often becomes apparent during the first cold spell of autumn when homeowners try to turn their heating on after several months of it being switched 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.
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A boiler cover plan would cover faults like 407 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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