For larger installations consideration may be given to the provision of Weather Compensator Control to help reduce fuel bills.
This type of control system uses a thermostat located outside the house and a 3-port mixing valve positioned close to the boiler.
The temperature of the flow water to the space heating circuits is adjusted according to the outside air temperature.
A low outside air temperature will direct the control system to supply the highest possible flow water temperature to the heat emitters.
When the outside temperature rises, the demand for space heating in the house will be reduced. The control system will cause the 3-port mixing valve to supply a lower temperature water to the space heating circuits.
A second type of control system, again for larger installations, an Optimeser Control measures the outside and inside temperatures and switches on the boiler and pump in anticipation of the heat energy demands of the building.
This form of control prevents the heating system operating unnecessarily when the outside temperature is relatively high and the building is already warm.