Boiler shows E10, heating and hot water disabled, pressure gauge indicates low or zero pressure.

Safety first: Allow the boiler to cool before topping up. Do not overfill the system.

User steps to restore pressure:

• Locate the filling loop (flexible hose or built-in valves) under the boiler.
• Open the filling valves slowly while watching the pressure gauge; fill to 1.2–1.5 bar when the system is cold.
• Close the filling valves completely and ensure there is no continuous water noise.
• Reset the boiler and check for normal operation.

If pressure keeps dropping:

• Inspect visible pipework and radiators for leaks.
• If no leaks are visible or E10 persists, a technician should check the expansion vessel, pressure sensor, and internal boiler components.

Technician checks:

• Test and, if necessary, replace the system pressure sensor on the hydraulic block.
• Check the expansion vessel pre-charge and recharge or replace if the diaphragm has failed.
• Inspect the boiler for internal leaks at the heat exchanger, pump, or safety valve.