Boiler shows E1 and shuts down shortly after starting

Safety first: Allow the boiler to cool completely. Turn off power before removing any covers. Do not bypass safety devices.

• Check system pressure: On the Remeha pressure gauge, ensure pressure is typically between 1.0–1.5 bar when cold. If low, top up via the filling loop according to the manual and bleed radiators.
• Bleed radiators: Use a radiator key to release trapped air starting from the lowest radiators. Re-pressurise the system as needed.
• Verify pump operation (sound/touch): With the boiler calling for heat, listen for the pump running and feel the pump body for vibration. If silent and cold, the pump may be seized or not powered.
• Check all valves: Ensure all isolation valves under the boiler and on the system are open so water can circulate.
• Engineer tasks: A heating engineer should check the pump electrically, clean or replace the primary heat exchanger if scaled or sludged, verify the flow NTC sensor readings, and inspect the overheat thermostat or safety cut-out.