Your boiler has lost its ability to accurately measure the water temperature inside the system, which is preventing it from heating up safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: A problem exists with the primary thermistor.
What causes this fault?
This fault occurs when the internal sensor responsible for monitoring water temperature fails or loses its connection to the main control board. The most common reason is that the sensor has simply worn out over time or the electrical pins have become corroded, preventing the boiler from knowing if the water is getting too hot. Because the boiler can no longer monitor safety temperatures, it shuts down to prevent any internal damage.
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 07 — no call-out fees, no surprises.
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