Boiler powers on but does not heat radiators; flow and return pipes remain cold.

Safety first: Isolate power before removing covers. Pipework may become hot unexpectedly.

• Check controls: Ensure the room thermostat and any programmer are calling for heat. Set them to maximum and continuous mode for testing.
• Verify boiler mode: On digital Elnur boilers, confirm that heating mode is enabled and not in frost or standby mode.
• Check pump operation: Listen for the pump running and feel for vibration. If silent, test for voltage at the pump terminals (qualified persons only). Replace the pump if it is not running with correct voltage.
• Check safety thermostats: Inspect and reset any manual safety thermostats. An open safety device will prevent element energisation.
• Test elements: If the pump runs but there is no heat, test the heating elements for continuity and replace any that are open-circuit.