The Ideal Heat Interface Units (HIU) are heat energy transfer units, designed for use in conjunction with centralised boilers, district heating or central energy systems. The function is to efficiently transfer heat from the plant room to the individual dwellings central heating (CH) and domestic hot water (DHW) systems. The Logic Direct HIUs are the latest 'intelligent’ range of HIU from Ideal. The Logic HIU is the complete solution for instantaneous hot water production and space heating control. The Direct wall mounted HIU, providing instantaneous priority direct hot water (DHW) and modulated central heating (CH)