A08
Fondital
Flow Sensor / Circulation Fault
Boiler shows A08, no heating or hot water, pump may run briefly then stop
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Blocked or stuck flow switch on Fondital hydraulic group, Air lock in primary circuit, Faulty circulation pump, Clogged system filter or dirt separator
How to Fix / Troubleshooting
Safety: Allow the boiler to cool before touching any pipework.
User checks:
- System pressure: Ensure pressure is within the recommended range (around 1.0–1.5 bar cold).
- Bleed radiators: Remove air from radiators to restore circulation.
- Check isolation valves: Confirm the heating flow and return valves under the boiler are fully open.
Technician actions:
- Inspect and clean the flow sensor / flow switch on the Fondital hydraulic assembly.
- Check operation of the circulation pump and replace if not delivering adequate flow.
- Clean or replace the system filter or magnetic dirt separator if fitted.
- Flush the heating circuit if sludge is suspected.
Advertisements
Repair Difficulty
Medium
3/5
Advertisements