To reduce the flow temperature of your heating, you need to turn the dial with the radiator icon down to the desired flow temperature. As mentioned, this will be around 60˚c for most homes. Some boilers like Worcester Bosch boilers will have dials that use a 1-6 numbering system rather than specific temperatures.
Ensure it is set to the appropriate temperature. Gradually increase the temperature setting and listen for a clicking sound, which indicates the thermostat is triggering the boiler. If the boiler doesn't respond or there is a significant temperature difference between the setting and room temperature, it might be a faulty thermostat. Step 2: Diagnosis based on the type of noise. The next step is to identify what type of noise your boiler is making. Often, diagnosing quickly and taking action where possible – based on unusual noises – can then help the further steps towards fixing the issue, helping to minimize complexity and potential cost.