CPC Subgroup
F24D 12/02 having more than one heat source (using heat pumps, in water central heating systems F24D3/18; in air central heating systems F24D5/12; in systems using heat storage masses F24D11/02)
Full Title
Other central heating systems > having more than one heat source (using heat pumps, in water central heating systems F24D3/18; in air central heating systems F24D5/12; in systems using heat storage masses F24D11/02)