Worcester
Inconsistent DHW Temperature Control
Boiler runs but hot water temperature fluctuates significantly during a shower, alternating hot and cold.
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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, faulty DHW flow sensor, diverter valve modulation issue, low or varying mains water pressure
How to Fix / Troubleshooting
Safety first: Risk of scalding; be cautious when testing hot water.
Homeowner checks:
- Run only one hot outlet at a time to see if stability improves.
- Ensure cold water mains stopcock is fully open.
Engineer actions:
- Measure DHW flow rate and compare with Worcester specifications.
- Inspect and descale or replace the plate heat exchanger.
- Test DHW flow sensor and replace if readings are unstable.
- Check diverter valve operation and modulation.
Stable DHW requires clean heat exchangers and accurate flow sensing.
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Repair Difficulty
Hard
4/5
Required Part
DHW Flow Sensor
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