The Base Unit should be installed in a convenient location where the majority of the system wiring is to be terminated, such as the cylinder cupboard or close to the boiler. It has knockouts to facilitate cable entry located on the left-hand side and rear for the line voltage wiring and on the right hand side and rear for Smartfit low voltage wiring. Do not run low voltage wiring across the printed wiring board or next to line voltage wiring. Remove the cover and mount using the two mounting screw positions.