Boiler displays E10; system pressure reading is low and boiler will not fire

Safety first: Allow the system to cool before adding water. Do not over-pressurize the system.

Steps to check:

• Check pressure gauge: Confirm the actual system pressure on the mechanical gauge (if fitted). If below the recommended level (often around 1.0–1.5 bar when cold), the system needs topping up.
• Top up the system: Locate the filling loop or filling valve on the Kospel boiler or system. Open the valve slowly to allow water into the system while watching the gauge. Close the valve when the correct pressure is reached.
• Bleed radiators: After topping up, bleed air from radiators and recheck pressure, topping up again if necessary.
• Inspect for leaks: Look for visible leaks at radiators, valves, and around the boiler. Repair any leaks found.
• Check pressure sensor: If the gauge shows correct pressure but E10 remains, the electronic pressure sensor or its connection may be faulty and require replacement.

When to call a technician: Persistent pressure loss or suspected internal boiler leaks should be investigated by a professional.