Sundial W Plan

The Sundial W Plan is designed to provide independent temperature control of both heating and domestic hot water circuits in fully pumped central heating installations. The W Plan uses a two position diverter valve which is normally installed to give priority to the domestic hot water circuit.


Because the W Plan is a priority control system, it is recommended that it should not be used when there is likely to be a high hot water demand during the heating season which could lead to the space temperature dropping below comfort level. This situation is likely to occur, for example, in large family dwellings or in poorly insulated properties.



  • Independent control of domestic hot water temperature
  • Pump and boiler switched off when space & hot water temperature requirements are satisfied
  • Reduces peak boiler demand as heating and hot water never operate simultaneously



  • Programmable thermostat in heating zone to provide 'Best Practice' system
  • Radiator thermostats may be fitted to provide temperature control in selected areas
  • evotouch can provide wireless boiler interlock for individual radiator control