Boiler shows E08, no heating, pump may run but burner does not start.

Safety: Allow the boiler to cool before adding water. Do not exceed the maximum system pressure indicated on the boiler label.

• Check pressure gauge: Look at the Klimosz pressure gauge or digital reading. If below ~1.0 bar (cold), the system needs topping up.
• Top up system: Open the filling loop valves slowly and watch the gauge rise to 1.2–1.5 bar. Close the valves firmly afterwards to prevent overfilling.
• Bleed air: Bleed radiators and the boiler’s automatic air vent. Recheck pressure and top up again if necessary.
• Inspect for leaks: Look under the boiler, around radiator valves, and at safety valve discharge pipe for signs of water. Repair leaks before repeated topping up.
• Check pressure sensor: If pressure is correct but E08 remains, inspect the pressure sensor wiring and connector. Replace the sensor if it does not change reading when pressure is varied.