Hi, I wonder if someone can help me. I have a Vaillant boiler which does not have a room thermostat. I have set the temperature of the heating through the relevant knob on the boiler at 50 degrees. The heating is set to be on permanently. On many occasions the main display shows a temperature lower than this setting, sometimes 40 or less. For the last couple of days, I have come home in the evening to find that the house is freezing cold and the temperature on the display is showing 18 degrees. The only way to get the heating going again is to turn the on/off knob from 1 to 0 and then back to 1. I do not know why this is if I have set the temperature higher. In addition I often see a flashing radiator symbol and do not know what that means or how it is relevant. Guidance would be appreciated. Thanks
