BoilerFaultCodesYour boiler has detected an issue with the sensor that monitors the water temperature in your main heating circuit, which may prevent your radiators from warming up correctly.
This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.
Technical description: Main zone water thermostat
What causes this fault?
This fault occurs when the boiler's internal computer receives an incorrect or missing signal from the sensor responsible for monitoring the heat of the water sent to your radiators. The most common reason is that the sensor has developed a technical fault over time or the electrical connection between the sensor and the main control board has become loose or damaged.
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 E077 — no call-out fees, no surprises.
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