Boiler shows H07, often related to low system pressure on some Worcester Bosch models.

Safety first: Allow the system to cool before repressurising.

• Check pressure gauge: If below 1.0 bar, use the filling loop (usually a braided hose or built-in keyless filling link) to slowly raise pressure to 1.2–1.5 bar.
• Close valves fully: After filling, ensure both filling valves are fully closed to prevent over-pressurisation.
• Inspect for leaks: Look around radiators, valves, and under the boiler for any signs of water.
• If pressure keeps dropping: Contact an engineer to locate and repair leaks and to test/replace the pressure sensor if readings are inconsistent.