An old FlaktWoods AHU that had severe degradation of its frame was replaced with a new Ciat unit. The chilled water and MTHW pipe work was modified and the mains power supply was renewed from a new control panel that was designed and built. The new AHU now has duty cycling on direct drive plug fans as opposed to the old unit having a single centrifugal fan being belt driven from a single motor. Dampers were fitted to the outlet of the plug fans so that duty cycling could be carried out via the BMS.