Error A08 appears, unit may start then quickly stop, sometimes accompanied by gurgling noises.

Safety: Turn off power and allow the system to cool before opening any water components.

• Check isolation valves: Confirm that the flow and return valves beneath the Fondital heater are fully open.
• System pressure: Verify that the pressure gauge shows adequate pressure. Top up via the filling loop if necessary, following the manual.
• Bleed air: Bleed radiators and any automatic air vents. Air in the system can stop circulation and trigger A08.
• Clean system filter: If your installation includes a return‑line filter or magnetic dirt separator, isolate it and clean out sludge and debris.
• Check pump: With power OFF, remove the pump’s front plug (if fitted) and gently turn the shaft with a screwdriver to free it. If the pump remains stuck or noisy, it should be replaced.