The City Multi Y-Series uses a 2 pipe system throughout the refrigeration network with the choice of  branch pipes or header pipes to feed indoor units for either cooling or heating operation. Manual change over from heating to cooling in response to the users requirements ensures a constant indoor climate. The system permits considerable flexibility allowing up to 16 indoor units which can be of different types to be connected to a single outdoor unit. The installed max. capacity of indoor units can range from 50% to 130% of the outdoor unit capacity.