Makes use of electronic expansion valve to exactly Command the move of R290 refrigerant in the evaporator as well as a four-way valve to divert the refrigerant flow for the defrost Procedure An air-to air process is usually intended to transfer heat in both way, to heat the inside of https://purethermal.co.uk/media-news/q4-launch-lithium-large-capacity-r290-ashp-from-pure-thermal-and-enerblue/