ACR Journal

CMYK / .ai CMYK / .ai CMYK / .ai acrjournal.uk 17 AIR CONDITIONING CASE STUDY 1: Cromwell House, London CBAC was awarded the PPM contract back in 2015 from Bilfinger FM (now Apleona FM) as one of their preferred suppliers. It was not long before CBAC realised that the site had a poor history with component failures on its Hitachi VRF systems throughout the eight floors, especially compressor and inverter boards. Having consulted Hitachi technical on several occasions, CBAC came up with a solution that would cost the client but give some peace of mind for the future. Hitachi pointed out that the new style of condenser would not communicate to the ducted indoor units without the replacement of the BC boxes. CBAC identified the worst offenders, 4 out of the 10 outdoor units and the 56 BC boxes. Craneage went smoothly on the day, with the addition of disconnecting a good condenser to make way for a new one. The decision was made to streamline the indoor BC works, which was all out of hours due the building being occupied, by removing the risk of hot works. CBAC purchased a Zoomlock kit from Greenmill AC supplies for pipe crimping on the refrigerant pipe work. The engineers worked in pairs and, by taking it turns, completed a system per week. CASE STUDY 2: L’Oreal London HQ CBAC has been servicing the two chillers since 2012 through the main FM companies on site. In recent years it has been difficult for the ageing chillers to maintain cooling in the building, due to the condition of the condenser coils. In 2016 the client requested all 24 condenser fans on both chillers be replaced with Ziehl Abegg Blue high efficiency fans to try and gain more air flow through the coils, followed by an adiabatic spray system to cool the air before going through the coils. Both works just prolonged the need to replace the coils. There was some additional work required while pressure testing each circuit as an engineer found weeping gaskets on the compressors. CBAC employed one of its business partners, Chris Page of AC Compressors, to carry out these works. All four circuits had new sight glasses and drier cores before finally evacuating and recharging. The Daikin screw compressors are all still operating well and, with the new coils, this chiller should last for many years. The CBAC Services team at their base in Rochford, Essex