Bosch EasyControl shows normal operation but the boiler does not fire for heating when there is a demand.

Safety first: Isolate power to the boiler and EasyControl before inspecting wiring.

• 1. Check operating mode: On the EasyControl and in the app, ensure it is not in holiday, eco, or frost-only mode. Set a higher target temperature and confirm a heat demand is shown.
• 2. Verify boiler settings: Confirm in the boiler menu that external controller mode (OpenTherm/EMS) is enabled and that internal scheduling is disabled if required.
• 3. Inspect wiring: Ensure the EasyControl is connected to the correct low-voltage control terminals on the boiler. If the boiler requires a simple on/off contact instead of OpenTherm, ensure a compatible Bosch relay interface is used.
• 4. Test boiler independently: Temporarily bridge the boiler’s thermostat terminals (if safe and per manual) to see if it fires. If it does, the issue is with the EasyControl or its interface; if not, the boiler has its own fault.

Professional help: If wiring and configuration are correct but the boiler still does not respond to EasyControl, a heating engineer should test the control interface and boiler electronics.