... -10 degrees ,Low temperature air to water heat pump can work at -20 degrees.AW09,AW09B,AW12,AW12B ... heat exchangerController: Siemens controller,Hiseer controllerElectronic parts: ScheiderExpansion valve: Emerson Dry filter: EmersonInternal differential pressure switchSoft starter ... heat pumpON LINE SYSTEM is optionalDaily hot water pump: Wilo water pump is optionalElectric heater: 3KW ,6KW,9KW is ...