How to adjust the DualSun solar controller coupled with an Ökofen pellet boiler?


The flow rate setting of the DualSun solar controller does not depend on the auxiliary system.
The Smart XS controller of the Ökofen boiler manages the solar energy natively. The specific documentation for the Smart XS-e Dual offer provided by Ökofen includes the DualSun recommendations.
The same control system manages the solar / DHW and heating priority to guarantee optimal operation of the system.


Indeed, a DualSun solar system allows to heat or pre-heat domestic hot water. However, depending on the solar contribution and/or the hot water consumption, it is always necessary to couple an additional solution with electric, gas, wood or other energy to cover all the needs.


The flow rate setting of the solar station is directly dependent on the sunshine conditions and the hot water temperature in the solar storage tank.
To find out the flow rate setting of DualSun systems according to the application.


  • The solar circulation pump management system allows the flow rate to be modulated according to the solar energy received and to be returned.
  • In order to optimize energy savings, the coupling gives priority to the solar thermal system to raise the water temperature.
  • The additional solar energy is used to supplement - or provide in case of insufficient solar energy - the energy input necessary to cover the need.
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