Makes use of Digital enlargement valve to exactly Management the flow of R290 refrigerant to the evaporator as well as a four-way valve to divert the refrigerant move for the defrost operation An air-to air program could be created to transfer heat in either route, to heat the inside of https://purethermal.co.uk/media-news/q4-launch-lithium-large-capacity-r290-ashp-from-pure-thermal-and-enerblue/