The 4, 6 and 8 kW models complement the existing 10, 13 and 16 kW heat pumps launched last year.
All Vitocal 150-A/151-A models provide both heating and cooling and are available to purchase for connection to single-phase electricity supply, with three phase models also available for the 10 to 16 kW variants.
Both the wall-mounted Vitocal 150-A and the floor-standing Vitocal 151-A with integral 190-litre DHW cylinder, have a maximum flow temperature of 70°C.
Darren McMahon, Viessmann Marketing Director, said: “The arrival of the 4, 6 and 8 kW models provides our installers with added flexibility to select the appropriately-sized product for homes with low heat losses, such as smaller or newer homes, or perhaps whole house retrofits.
