Abstract: A chiller system includes a compressor operable at a compressor speed between a first speed and a second speed to deliver a flow of compressed fluid to a manifold at a compressor pressure and a condenser in fluid communication with the manifold to receive the compressed fluid. A condenser fan is operable at a fan speed between a minimum fan speed and a maximum fan speed to direct a cooling flow to the condenser to cool the compressed fluid and an evaporator is positioned to receive the flow of compressed fluid and operable to cool a second fluid. A controller is operable at least partially in response to a measured temperature of the second fluid and a measured temperature of the cooling flow to determine a desired pressure and to vary the compressor speed and the fan speed such that the compressor pressure equals the desired pressure.