We have a combi boiler and radiators with individual thermostats, but no temperature thermostat which we can set to a certain level. All radiators are set on No. 3. In our lounge and dining room the temperature reaches 20 degrees, but the rest of the house is in the region of 15 degrees. The boiler is in the kitchen which opens out into the hall. There is an unmarked dial marked 1-6 and it is set on 1.5. Does this control the temperature of the area surrounding the boiler, or is it done on the radiators? I just wondered, given that there is a great difference in the temperatures reached.