Ferroli No DHW Production on Combi Boiler

Boiler runs for central heating but does not provide hot water on a combi model, with no error code.

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.

Possible Causes

Faulty DHW flow switch or turbine, Stuck diverter valve, Blocked plate heat exchanger, DHW NTC sensor fault

Safety first: Isolate power and water before any internal work.

Check DHW demand: Open a hot tap fully and observe the boiler; if it does not recognise demand (no flame symbol or burner start), the flow sensor may be faulty.
Engineer checks:
- Test and replace the DHW flow switch/turbine if not signalling flow.
- Inspect and free or replace the diverter valve if stuck in heating position.
- Clean or replace the plate heat exchanger if blocked.
- Test DHW NTC sensor and replace if defective.

Hard 4/5

Diverter Valve Assembly

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