Heating and domestic hot water; Adopt Siemens controller, easily understandable control Internal 3 way revert valve and hot water pump are optional for 8-15KW units Internal Electric heater is optional Daikin/Hitachi R410A Scroll compressor; Swep Plate type heat exchanger; Rust free galvanized sheet case Varied heat curve Well design of inner structure, fixing and insulation to assure low noise for indoor installation.