Ready-to-install ultrapure water unit, consisting of a reverse osmosis system with directly connected electrodeionisation for final demineralisation of the permeate. The system is fitted on a sturdy aluminium frame and is optionally available with cladding and a transparent inspection door. The system is controlled and monitored using a PLC with a touch screen panel. The most important process data (e.g. conductivity and flow rate) are available as analogue values for the central control room via PROFINET.