I've set up weather comp with a viessmann 100-w B1KF (2021 model) with a thermostat. The thermostat temp reads 22.1c, the boiler's desired room temp is set to 23c. However, I have notice that the boiler will run for 20min then the burner turns off whilst the pump is still running, then 10-20min later, the burner turns back on. This is all great but I was expecting the burner to run continuously until it hits the desired 23c. At the moment, it doesn't exceed 22.3c - What gives ?