BoilerFaultCodesYour boiler has lost communication with its external heating controls, meaning it is struggling to understand when it should be turning on or off.
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: E-Combi EvoE-System EVOClas HE evo CombiClas HE evo System
What causes this fault?
This fault occurs when the boiler's main control board loses its digital connection with the external thermostat or wireless receiver. The most common reason is a loss of power to the thermostat, signal interference, or a physical wiring failure between the receiver and the boiler. Because the boiler can no longer receive instructions on when to heat your home, it may revert to a safety mode or stop firing entirely.
DIY fix possible
Check batteries in your wall thermostat or programmer.Ensure the heating controls are within range of the boiler.Turn the boiler off at the main switch, wait 30 seconds, and turn it back on to reset the connection.
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 702 — no call-out fees, no surprises.
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