Crown
Insufficient DHW Output
Boiler runs but domestic hot water is not hot enough on a Crown combi boiler
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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.
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Possible Causes
Scaled plate heat exchanger, DHW temperature set too low, Faulty DHW sensor, Flow rate too high for boiler capacity
How to Fix / Troubleshooting
Safety: Hot water can scald. Use caution when testing DHW temperature.
- Check DHW setpoint: On the Crown control, verify the domestic hot water temperature setting. Increase slightly if too low, staying within safe limits (typically 120–130°F / 49–54°C).
- Reduce flow: Open hot taps less fully to reduce flow rate and allow more heating per gallon.
- Clean inlet filter: Some combi boilers have a cold water inlet filter. Isolate and clean it to ensure proper flow through the plate heat exchanger.
- Descale plate exchanger: In hard water areas, a professional should chemically descale the DHW plate heat exchanger.
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Repair Difficulty
Medium
3/5
Required Part
DHW Plate Heat Exchanger
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