Boiler provides heating but no domestic hot water, or hot water is only lukewarm, no error code.
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.
Possible Causes
How to Fix / Troubleshooting
Safety first: Turn off power and close the cold water inlet before removing DHW components.
User-level checks:
- Run a hot tap fully open and check if the boiler display indicates a DHW demand (tap symbol, temperature change).
- Ensure cold inlet and hot outlet isolation valves under the boiler are open.
Technical checks (qualified personnel):
- Test the DHW flow sensor for correct operation and replace if not detecting flow.
- Check diverter valve movement; if stuck in CH position, repair or replace the valve.
- Inspect and descale the plate heat exchanger if partially blocked.
- Verify DHW NTC sensor readings and replace if faulty.
After repair, test hot water at multiple outlets to confirm stable temperature and flow.
Repair Difficulty
Required Part
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