New WSG-Duo-2 unit

Rather than pipe very hot water around a building from a central store this product allows you to drop the temperature down to 45 degrees and then top it up at point of use. This not only means reducing heat losses from pipework, but also, as a lower hot water temperature is required from the central plant, a heat pump running at high efficiency can be used to produce the hot water. This heat interface unit with integrated instantaneous domestic hot water heater is now available in a 3 phase (commercial electricity) unit, with a single phase (domestic electricity supply) unit to follow.



  • Lower distribution temperature increases efficiency
  • High hot water temperatures up to 60°C
  • Endless supply of hot water
  • Good flow rates - up to 17 l/m at 42°C
  • Enables the efficient use of renewable technologies for lower carbon footprint and better SBEM scores

System design

  • Central plant for heating and hot water with hot water ‘top up’ in the apartment.
  • DHW temperatures up to max. 60°C
  • Heating distribution system could be:
  1. Underfloor heating                    
  2. Underfloor heating and/or radiators



  • Flow temperatures from central plant between  38°C and 45°C
  • Heat generator could be:
  1. Heatpump
  2. Fossil fuel boiler



  • Allows the distribution temperature from a central plant to be reduced – saving energy.
  • Copes with changing flow temperatures from the central plant - acts as a ‘top up’
  • Distribution temperatures from a central plant can be reduced to suit heat pumps technology.
  • Because it acts as a ‘top up’ the electrical requirement is low.
  • Piped with a bypass valve to reduce pressure loss