Utilizes Digital expansion valve to precisely Handle the movement of R290 refrigerant in to the evaporator as well as a 4-way valve to divert the refrigerant move to the defrost Procedure By Pressing submit, I consent that my data be shared with Trane authorised affiliate marketers and 3rd party partners, https://purethermal.co.uk/media-news/q4-launch-lithium-large-capacity-r290-ashp-from-pure-thermal-and-enerblue/